# Lelit Mara X - Flow Control Kit



## shaunlawler

I have had my Lelit Mara X for a few months now and really enjoying it paired with a Niche Zero.

However, I would like to experiment more with flow control and debating whether to add a flow control kit (the one made for the Lelit Bianca). There are a few people who have done this and I have heard mixed results, most negatives being that it is not as effective on the Mara X as it is on the Bianca.

Does anyone that has installed this have any advice on whether it is worth it or not?

The below is the kit I am looking at purchasing to fit:

https://www.espressounderground.co.uk/Bianca-Kit-Flow-Control-Assembly-p/le1000185-fk.htm

Appreciate any advice!


----------



## DavecUK

Easy to fit and should work well. You would be well advised to read my review and there is another one where I fitted it to a Minima, useful for some fitting tips etc..definitely recommend you read it and watch the vids.

https://coffeeequipmentreviews.wordpress.com/2019/07/29/lelit-needle-valve-kit/


----------



## shaunlawler

DavecUK said:


> Easy to fit and should work well. You would be well advised to read my review and there is another one where I fitted it to a Minima, useful for some fitting tips etc..definitely recommend you read it and watch the vids.
> https://coffeeequipmentreviews.wordpress.com/2019/07/29/lelit-needle-valve-kit/


Thanks @DavecUK

To be honest, it was your videos and reviews that persuaded me to get a Lelit Mara X (including the Niche Zero and Osmio Zero).

My bank balance as a result has depleted but the quality of my coffee has increased exponentially!

Your cleaning/maintenance videos have also been extremely helpful. Thank you.

Sent from my iPhone using Tapatalk


----------



## Doram

shaunlawler said:


> Does anyone that has installed this have any advice on whether it is worth it or not?
> 
> The below is the kit I am looking at purchasing to fit:
> 
> https://www.espressounderground.co.uk/Bianca-Kit-Flow-Control-Assembly-p/le1000185-fk.htm


 I think you can get a similar thing cheaper, for example this kit from Coffee Sensor for 150 Euros, which is claimed to fit Mara X: https://coffee-sensor.com/product/coffee-sensor-flow-control-device-for-e61-groupheads/. I think @kico might have one, and maybe other forum members as well.

Would love to hear experience from others who tried it as well.


----------



## Northern_Monkey

@Doram - Worth a note the coffee sensor site excludes Lelit e61 as compatible if I remember correctly - edit they have changed their wording now to include Lelit as compatible 😂

Not all tolerances on all machines play nice, I tried an ECM/Profitec stainless paddle set on my older Mara and it let water past the injector ring so didn't lock off fully. But it has worked for others on their Mara-x

Still a bit of a punt cross brands as it has been OK for other people but there is some variability on e61s so not 100% guaranteed.


----------



## Doram

Northern_Monkey said:


> @Doram - Worth a note the coffee sensor site excludes Lelit e61 as compatible if I remember correctly.


 I think it's the other way around: They specifically say it's tested and works with Mara X:


----------



## shaunlawler

Thank you for highlighting the other version that's slightly cheaper - always good to save a bit of money on coffee gear!

If I do install one, I would likely go for the Lelit paddle version, as although it may not perform any different, it will match the other wood accents and I prefer the look of the manometer.

I would be really interested in hearing from anyone who has the Mara X and has installed this flow paddle kit.


----------



## MediumRoastSteam

shaunlawler said:


> Thank you for highlighting the other version that's slightly cheaper - always good to save a bit of money on coffee gear!
> 
> If I do install one, I would likely go for the Lelit paddle version, as although it may not perform any different, it will match the other wood accents and I prefer the look of the manometer.
> 
> I would be really interested in hearing from anyone who has the Mara X and has installed this flow paddle kit.


 @Stanic did. But I haven't seen him around in a while - I'm not sure if he installed the Lelit version though.


----------



## Northern_Monkey

@Doram - I checked again after I posted originally and edited it to reflect that. The wording has now been updated to include Lelit Mara/Mara-x, they didn't say it was compatible originally and I think actually excluded it. The sales blurb has changed, more text and detail than when it first got released.

@MediumRoastSteam - Stanic has the ECM/Profitec one fitted to his Mara-x, working perfectly for him but no dice on my older one.


----------



## MediumRoastSteam

Northern_Monkey said:


> @Doram - I checked again after I posted originally and edited it to reflect that. The wording has now been updated to include Lelit Mara/Mara-x, they didn't say it was compatible originally and I think actually excluded it. The sales blurb has changed, more text and detail than when it first got released.
> 
> @MediumRoastSteam - Stanic has the ECM/Profitec one fitted to his Mara-x, working perfectly for him but no dice on my older one.


 Now you say it... I vaguely remember you guys talking about it. 👍


----------



## kico

@Doram

I installed it a few days ago. Still getting the hang of it but it has completely changed my espresso game.....

I've been looking at whole latte love YouTube videos showing the different types of profiles.

I love doing an extra slow ramp up and then tapering off at the end of, it has eliminated extra sourness and brightness from lighter roasts that I really disliked before.

The sweet bump profile is night and day before you add milk. I love iced americanos so it makes a huge difference for me.

I'd really recommend the coffee sensor flow control. Comes with 2 different handle options, the owner is really nice too and sent me instructions / is super responsive on WhatsApp. Delivery was quick!

Personally, I dislike wood so this colour is perfect for me. I love the black / silver theme.

I was having doubts that I should've purchased the Elizabeth a month ago, almost regretting not getting the Elizabeth over the mara x. After doing the water saving mod, and now the flow control (quite literally life changing) I know I made the right decision!

Love my mara x now and very excited to play around with the flow control more / learn to be more consistent. It really makes it difficult to produce a bad shot.

Just a note - see this thread:

https://www.coffeeforums.co.uk/index.php?app=core&module=system&controller=embed&url=https://www.reddit.com/r/espresso/comments/ha9grj/e61_flow_control_kit_versions/

The turn is like the quickmill flow control. The range is very limited so precise control is harder. I think it really is possible and quite easy. This is nearly half the price of the Lelit one.

I find just turning it 120 degrees / 1/3rd makes it reach 9 bars of pressure. I think this is better for this style as the metal part still gets very hot, so you don't burn yourself by trying to turn the plastic handle around. It is still easily possible to slowly ramp it up with gentle movements, and you can more quickly lower the pressure / completely shut it off (which I prefer) to finish the shot just using the flow control rather than the lever.

With manual flow control there is only so much precision you can have. This allows you to do everything you'd need to do, efficiently, with little effort, once you get the hang of it of course!

















Sent from my SM-G975F using Tapatalk


----------



## Andrewczy

Can agree with the above.

Recently installed the Coffee Sensor flow kit on the Mara X with no issues. Seems much easier to install compared to the Lelit kit. I definitely enjoy playing around with the extra variable, gives espresso making a much more ' hands on feel '.

@kico, did you change the bottom spring or leave the Mara X one in?


----------



## kico

Andrewczy said:


> Can agree with the above.
> 
> Recently installed the Coffee Sensor flow kit on the Mara X with no issues. Seems much easier to install compared to the Lelit kit. I definitely enjoy playing around with the extra variable, gives espresso making a much more ' hands on feel '.
> 
> @kico, did you change the bottom spring or leave the Mara X one in?


 I followed the instructions so I changed the spring. It removes the Mara X pre infusion so I can control the ramp up.

Currently I'm liking doing a really slow 20 second pre-infusion up to 4bars, and then taking it up to 8 bars over 10 seconds, hold for 5 seconds, and then slowly drop it down to finish the shot fully closed, ignoring the final timer, focusing on 1:2 ratio. Getting absolutely fantastic results!


----------



## shaunlawler

Is there any benefit to the Coffee Sensor option over Lelit apart from the price?


----------



## kico

shaunlawler said:


> Is there any benefit to the Coffee Sensor option over Lelit apart from the price?


 You get the option of 2 handles, a fixed one and one that flips 180c.

Also the colour scheme - it is black and metal. Matches the stock handles of the Mara X.

I think it is slightly easier to install? You need a big adjustable spanner for the mushroom head - 350mm (maybe 360mm just to be safe).


----------



## shaunlawler

If there isn't a downside in usability, I think the Lelit wooden version would fit my current set up more...


----------



## kico

shaunlawler said:


> If there isn't a downside in usability, I think the Lelit wooden version would fit my current set up more...


 Since you have the wooden handle, wooden objects that I do not know on the left, and the niche it would match quite nicely. Visually that would be your best bet.

I almost want to change the colour of the wood on my niche to black to match my mara x / tamper.


----------



## kico

Lelit flow control looks very simple to use. It would be nice if they offered a black handle.

It does seem simpler once installed / nice and linear. Not sure if it is worth so much more, I personally wouldn't pay that much extra for it especially not in black, but It seems like a great option for anyone with the wooden accessory kit.


----------



## Rob1

shaunlawler said:


> I have had my Lelit Mara X for a few months now and really enjoying it paired with a Niche Zero.
> 
> However, I would like to experiment more with flow control and debating whether to add a flow control kit (the one made for the Lelit Bianca). There are a few people who have done this and I have heard mixed results, most negatives being that it is not as effective on the Mara X as it is on the Bianca.
> 
> Does anyone that has installed this have any advice on whether it is worth it or not?
> 
> The below is the kit I am looking at purchasing to fit:
> 
> https://www.espressounderground.co.uk/Bianca-Kit-Flow-Control-Assembly-p/le1000185-fk.htm
> 
> Appreciate any advice!


 You can get the kit much cheaper and likely much quicker here: https://www.lamacchinadelcaffe.com/en/home.html


----------



## shaunlawler

Rob1 said:


> You can get the kit much cheaper and likely much quicker here: https://www.lamacchinadelcaffe.com/en/home.html


Thanks but this looks more expensive to my eye, unless I am missing something?

To buy the same kit, you need to purchase the flu regulator with paddle (€183) and the manometer kit (€60). Adding shipping at €18 brings the total to £237 converted to £ which is slightly more than £236.72 which includes free shipping.

Also I am not sure this would be quicker than a U.K. company shipping wise, although I have no experience with Espresso Underground.

I would be interested in hearing more views from people who have done this and whether they feel it's worth it.

Maybe I need to look at another machine, like the Decent, if I want to get into espresso profiling but this seems like a good way to simply get into it a little bit and dip my toes in.


----------



## MediumRoastSteam

shaunlawler said:


> Also I am not sure this would be quicker than a U.K. company shipping wise, although I have no experience with Espresso Underground.


 Drop them an email and confirm the item is actually in their warehouse before committing if time is an issue.


----------



## Rob1

shaunlawler said:


> Thanks but this looks more expensive to my eye, unless I am missing something?
> 
> To buy the same kit, you need to purchase the flu regulator with paddle (€183) and the manometer kit (€60). Adding shipping at €18 brings the total to £237 converted to £ which is slightly more than £236.72 which includes free shipping.
> 
> Also I am not sure this would be quicker than a U.K. company shipping wise, although I have no experience with Espresso Underground.
> 
> I would be interested in hearing more views from people who have done this and whether they feel it's worth it.
> 
> Maybe I need to look at another machine, like the Decent, if I want to get into espresso profiling but this seems like a good way to simply get into it a little bit and dip my toes in.


 If you buy the wildly overpriced manometer, sure. You could get the Oman one for about £10 (Manometer for group E-61 D.40 Cod. LP5530011) or the one from coffee sensor for about £19.

I speak from experience. As MRS says contact them and ask if they actually have it in stock. I've received things with free postage from China faster. Also the paddle arrived scratched by the grub screw left floating about in the bag.

If you really want the Lelit manometer I have one I could sell you from my kit unused.


----------



## Doram

kico said:


> I installed it a few days ago. Still getting the hang of it but it has completely changed my espresso game.....


 Thanks @kico, great write up. A few more posts like that and I will have to get one for my birthday....


----------



## Glen

I would love to order one of these kits from Coffee Sensor, does anyone know if the black knob can be unscrewed and replaced with a wooden one? I'll probably still order one anyway though...


----------



## fitzgerald91

Glen said:


> I would love to order one of these kits from Coffee Sensor, does anyone know if the black knob can be unscrewed and replaced with a wooden one? I'll probably still order one anyway though...


 I would think the chance is high it fits. I have the original Lelit Kit, but I know another MaraX owner who has the ECM flow control kit and uses the Lelit paddle...


----------



## zellleonhart

Glen said:


> I would love to order one of these kits from Coffee Sensor, does anyone know if the black knob can be unscrewed and replaced with a wooden one? I'll probably still order one anyway though...


 Even if it fits, isn't the Coffee Sensor version's thread being finer, meaning to go from zero flow to full flow it takes more than 180 degree turn. Hence the wooden knob will be blocked by the machine's body? I see people turning more than 360 degree using the Coffee Sensor kit.


----------



## DavecUK

@zellleonhart you need to be careful, full flow on these kits exceeds the flow rate of a standard gicleur on the top of an E61 group.

The max flow rate is not necessary to produce a normal shot and I'm not sure the thread is different.


----------



## cuprajake

As above you dont need more that a full turn to do your desired shot

Mine was fully closed at 3 o'clock

If i opened anti clock wise, to about 10 this would infuse to about 2/3 bar, id then go to 12 to hold it then round to about 6 to finish the shot.


----------



## zellleonhart

DavecUK said:


> @zellleonhart you need to be careful, full flow on these kits exceeds the flow rate of a standard gicleur on the top of an E61 group.
> 
> The max flow rate is not necessary to produce a normal shot and I'm not sure the thread is different.





Cuprajake said:


> As above you dont need more that a full turn to do your desired shot
> 
> Mine was fully closed at 3 o'clock
> 
> If i opened anti clock wise, to about 10 this would infuse to about 2/3 bar, id then go to 12 to hold it then round to about 6 to finish the shot.


 I see, I don't know to what extent is it considered "full flow". I use the official Lelit flow control kit on my Mara X so to the right end of the knob, it gives me 9.5 bar (my OPV setting) so I assume that it full flow.

I just assumed that the Coffee Sensor's kit will need to turn more degrees to achieve the same control with the Lelit's one, from what I observed in videos online. I could be wrong!


----------



## cuprajake




----------



## DavecUK

@zellleonhart Pressure and flow are different. 9.5 bar can be achieved with a wide range of flow rates. Against a blind filter for example...0.1 ml per second or 100 ml per second can achieve 9.5 bar. It depends on the resistance of a coffee puck.

A coarse ground puck at a very high flow rate might generate 9 bar resistance at a very high flow rate, whereas a fine ground puck may generate the same resistance at a much reduced flow rate. Espresso only needs a flow less than 1.5ml per second through the puck.


----------



## Glen

DavecUK said:


> @zellleonhart you need to be careful, full flow on these kits exceeds the flow rate of a standard gicleur on the top of an E61 group.
> 
> The max flow rate is not necessary to produce a normal shot and I'm not sure the thread is different.


 I will soon have my Coffee-Sensor flow control kit, do you have a description of how to avoid exceeding the maximum correct flow rate? TIA


----------



## DavecUK

@Glen Don't worry, just use the kit, it I'll all take care of itself.


----------



## Glen

DavecUK said:


> @Glen Don't worry, just use the kit, it I'll all take care of itself.


 OK thanks, what I plan to do is stop opening it any further than when the gauge reads 8 bar anyway... And have you watched the latest review of coffee machines by Matt Hoffman? He's finally tried out the Mara X. Although it's all a little rushed and he doesn't seem to have been able to spend enough time with the Mara to fully appreciate it's complexities. One thing he found interesting was that the pump pressure gauge seemed to be exactly what his Skace 2 was reading. Has this been discussed somewhere already? Have Lelit done something unique here with how the Mara pressure gauge reads?


----------



## MediumRoastSteam

Glen said:


> Matt Hoffman?


 Do you mean James?

https://www.coffeeforums.co.uk/topic/60493-hoffmans-%C2%A31500-espresso-machines/?do=embed#comments


----------



## Glen

MediumRoastSteam said:


> Do you mean James?
> 
> https://www.coffeeforums.co.uk/topic/60493-hoffmans-%C2%A31500-espresso-machines/?do=embed#comments


 oops! I'm always doing that! Matt H. was big when I was a kid, fan of BMX... lol

Thanks for the link too, I'll have a read.


----------



## oko

These look interesting. I'm got to stick with the stock Mara setup until Christmas I think then get a gift from me to me. Enjoy/get to know it it as factory setup until then. Bar the water reroute mod. Save the planet.


----------



## Glen

So... I thought I knew how this works, just turn the tap open and closed and watch the little manometer to see what the pressure is doing... but then @DavecUK said something about the flow possibly being more than the standard valve would allow... and I started looking for more info. I found that there is actually a good video about *flow *control, by Whole Latte Love on youtube in which Marc explains that you can measure the amount of water coming out of the group per second and then know how to plan your flow rates by something like a quarter turn.

In a reply to my comment on the Whole Latte Love video, Marc said: "Brew pressure and flow rate are related. If I pull a number of shots using the same grind size using different brew pressures the flow rate through the grind will change. So contact time of brew water with the coffee changes. If I change my grind size a bit and I use the same brew pressure contact time of brew water with the coffee changes. If I change grind size and control the flow I can keep brew water contact time the same even though grind has changed. In my experience and in research test results there is little difference in standard extraction quality (as measured by TDS) in a range of ~6-10bar of brew pressure but a big difference in quality with changes in flow rate. By focusing less on brew pressure and more on flow one reduces the number of variables. Flow rate has more impact on extraction quality than brew pressure. Marc"

Sorry if I'm stating the obvious here, but I just feel like all the videos I had seen already on this device show the focus being on what the manometer is saying, not considering the flow at all. I am now thinking it's probably more effective to follow the flow based method that I saw in the Whole Latte Love video. There are probably other videos out there which I haven't found too. I watched the erroneously named "How to use" video by Bella Barista about the Bianca flow control paddle, where he actually spends most of the time telling us that he has set it up with highly trained technicians to be perfectly set up and that the owner should not mess with it after they receive it... I thought the video was supposed to be about "how to use" it. But he did mention briefly that it's not for pressure profiling, but rather for flow, just before he got distracted from the whole point of the video... lol


----------



## zellleonhart

Glen said:


> So... I thought I knew how this works, just turn the tap open and closed and watch the little manometer to see what the pressure is doing... but then @DavecUK said something about the flow possibly being more than the standard valve would allow... and I started looking for more info. I found that there is actually a good video about *flow *control, by Whole Latte Love on youtube in which Marc explains that you can measure the amount of water coming out of the group per second and then know how to plan your flow rates by something like a quarter turn.
> 
> In a reply to my comment on the Whole Latte Love video, Marc said: "Brew pressure and flow rate are related. If I pull a number of shots using the same grind size using different brew pressures the flow rate through the grind will change. So contact time of brew water with the coffee changes. If I change my grind size a bit and I use the same brew pressure contact time of brew water with the coffee changes. If I change grind size and control the flow I can keep brew water contact time the same even though grind has changed. In my experience and in research test results there is little difference in standard extraction quality (as measured by TDS) in a range of ~6-10bar of brew pressure but a big difference in quality with changes in flow rate. By focusing less on brew pressure and more on flow one reduces the number of variables. Flow rate has more impact on extraction quality than brew pressure. Marc"
> 
> Sorry if I'm stating the obvious here, but I just feel like all the videos I had seen already on this device show the focus being on what the manometer is saying, not considering the flow at all. I am now thinking it's probably more effective to follow the flow based method that I saw in the Whole Latte Love video. There are probably other videos out there which I haven't found too. I watched the erroneously named "How to use" video by Bella Barista about the Bianca flow control paddle, where he actually spends most of the time telling us that he has set it up with highly trained technicians to be perfectly set up and that the owner should not mess with it after they receive it... I thought the video was supposed to be about "how to use" it. But he did mention briefly that it's not for pressure profiling, but rather for flow, just before he got distracted from the whole point of the video... lol


 A lot of the youtube videos out there are not detailed or nuanced enough especially those coming from retailers.

My understanding is, the flow profiling kit (as its name suggests) alters the opening size of the gicleur, hence changing the flow rate of water going into the puck. The pressure showing on the group head manometer can act as a feedback once the puck is about to be *fully saturated* when the puck creates enough resistance.

I refer to this very detailed guide for my initial flow profiling learning - https://espressoaf.com/guides/profiling.html in which it describes in detail on how water debit and flow profiling works.

My current preferred method is the "modified dipper" profile, where I fully saturates the puck using almost double of the coffee used (e.g 16g beans = 32ml water debit), with my MaraX's max flow rate of 4.5ml/s it takes about 6-7 seconds. Then I reduce the flow rate to about 1ml/s to continue the slow preinfusion until the first drips, and it should be around 2-4 bar pressure showing on the manometer (*a kind of feedback to guide you, but not absolute*). After that I go with the full flow and taper at the end


----------



## Doram

Glen said:


> I watched the erroneously named "How to use" video by Bella Barista about the Bianca flow control paddle, where he actually spends most of the time telling us that he has set it up with highly trained technicians to be perfectly set up and that the owner should not mess with it after they receive it... I thought the video was supposed to be about "how to use" it. But he did mention briefly that it's not for pressure profiling, but rather for flow, just before he got distracted from the whole point of the video... lol


 Just to make sure you didn't misunderstand the video: when Martin says the paddle is set by technicians so don't change it as it can cause damage - he means don't take the paddle off and change its position in an attempt to be able to stop the flow completely when the paddle is moved to the left. He doesn't mean one shouldn't play with the paddle (as set by technicians) to change the flow when pulling a shot. 🙂 Sorry if this was obvious, but I though it would be good to mention just in case, lol.


----------



## Glen

I got my Coffee Sensor kit yesterday and installed it. I took all the measurements of flow rate:

Original stock full flow 5.3 ml/s

With Coffee Sensor kit installed, tap opened:

1/4 turn: 2.05 ml/s

1/2 turn: 3.75 ml/s

3/4 turn: 4.4 ml/s

1 full turn: 4.95 ml/s

1 & 1/4: 5.11 ml/s

1 & 1/2: 5.3 ml/s = Original Full Flow

I made our morning coffees today and enjoyed the fun, the results tasted good too. Still need to experiment a lot more to see if I am capable of tasting the difference in different profiles.

One thing I wanted to ask though, when I removed the ciglure, I found that it has signs of calcification or something, any ideas? Our water here is very good, we don't get white marks left on glass from dried water and our kettle doesn't get scale in it, so I'm wondering if this is from our water or could have formed from the water used in testing prior to my use.


----------



## Tjyven

@Glen If you open as much as possible what flow rate do you get then?


----------



## MediumRoastSteam

Glen said:


> so I'm wondering if this is from our water or could have formed from the water used in testing prior to my use.


 Only one way to find out: clean it all up and check after a couple of months again. 👍

I suppose even with a small amount of minerals you might get spots as the water heats up inside the HX at temperatures above boiling point. Don't forget the water circulates at 130C or so during warm up.


----------



## Tjyven

@kicoWhen doing your slow ramp up what flow rate do you reach before tapering off?


----------



## prezes

I just got my hands on a coffee sensor flow control kit and about to fit it this evening. I watched @DavecUK videos on the Lelit kit and importance of lubricating prior to fitting. I don't know how to do it on this kit.

I don't know how to split it and I'm afraid of damaging it.

can someone give me an idiots guide please ?


----------



## DavecUK

part A unscrews from part B, use a spanner on the flats in part A. It can be on really tight, when replacing use a wrap or 2 of PTFE so it releases easy next time, or try MolyKote on the threads.


----------



## prezes

@DavecUK thank you very much !


----------



## prezes

I was wondering about the correct way to measure the flow rate and can't find information on this which would be definite. 
Should you start timing from first drop in the container or from starting the pump ?

This is what I'm getting although strangely this can vary as I run it few times. Figure without brackets is timing 20 seconds from first drop in container, in brackets timing from starting the pump.

1 & 1/4 turn - 5.7ml/s (5.075ml/s)

1 turn - 5.31ml/s (5.04ml/s)

3/4 turn - 5ml/s (4.68ml/s)

1/2 turn - 3.7ml/s (3.54ml/s)

1/4 turn - 2ml/s (1.72ml/s)


----------



## DavecUK

Obviously you are talking without coffee or portafilter loaded?

You should time flow rate from a point where the flow is properly started.... It's the only consistent standard you can get. So say after 5 seconds once things have settled down....start measuring


----------



## prezes

@DavecUK thank you I will try it again this morning.


----------



## prezes

Tried it again starting the timer after 3-5 seconds when the flow seemed consistent:

1/4 turn - 2.27ml/s

1/2 turn - 4.3ml/s

3/4 turn - 5ml/s

1 turn - 5.65ml/s

Didn't go further as this already exceeds the stock full flow. 
what makes me think is when starting a shot with this set at full turn the pressure gauge seems to be jumping quicker to 3 bar. On a standard shot without flow control fitted it riser gradually to this point as well. To achieve similar effect it has to be set to 1 & 1/4 turn. 
Should I just ignore this or is there any logic behind that ?

https://youtube.com/shorts/-a3wIUcjVX4?feature=share


----------



## DavecUK

@prezes If you have less restriction in the group and a higher initial flow rate, then the gauge will jump a little quicker. Don't worry about it.


----------



## Bicky

So my Coffee Sensor flow control device is on the way and I wanted to get clarification on a couple of things -



I've measured my standard flow rate at 5.55 ml/s - I assume I should avoid exceeding this with the device installed? (is this even possible?)


In that BellaBarista video and on the HB forum, there's some discussion about avoiding closing the valve completely to avoid mechanical damage, is this a valid concern? Should you always leave it open at least a quarter turn? I've seen/read of lots of people closing it entirely (not on the Bianca, but other machines).


Thanks!


----------



## DavecUK

@Bicky You should set it so you can close it completely. You won't damage the machine, otherwise no one could ever backflush an E61 style group.


----------



## natdev34

@Bickyi know this isn't a customs forum but would be interested to hear what type of additional fees you end up having to pay to receive the product? Thinking through lots of scenarios for a new machine myself which includes getting the coffee sensor kit


----------



## Bicky

natdev34 said:


> @Bickyi know this isn't a customs forum but would be interested to hear what type of additional fees you end up having to pay to receive the product? Thinking through lots of scenarios for a new machine myself which includes getting the coffee sensor kit


 It's arrived, no additional fees, so about £150 all in. I think it's just your luck with this stuff sometimes. Personally I'd expect the worst, but hope for the best!


----------



## Doram

Bicky said:


> So my Coffee Sensor flow control device is on the way and I wanted to get clarification on a couple of things -
> 
> 
> 
> I've measured my standard flow rate at 5.55 ml/s - I assume I should avoid exceeding this with the device installed? (is this even possible?)
> 
> 
> In that BellaBarista video and on the HB forum, there's some discussion about avoiding closing the valve completely to avoid mechanical damage, is this a valid concern? Should you always leave it open at least a quarter turn? I've seen/read of lots of people closing it entirely (not on the Bianca, but other machines).


 I have the same machine as you (Mara X) with Coffee Sensor's flow control device. I *can* close the valve to completely stop the flow, but I never do. I *can also* exceed the stock flow rate of the machine, and I never do that either. The range I use is from between 1/4 or 1/3 of a turn from fully closed (minimum flow) to about 1 full turn from fully closed (maximum flow). In other words, the total range I use is about 3/4 of a turn. Have fun with your new toy. 



natdev34 said:


> @Bickyi know this isn't a customs forum but would be interested to hear what type of additional fees you end up having to pay to receive the product?


 I got mine from Blue Star coffee. They are in Ireland, Delivery is free over €100 and they also automatically take off their local VAT (23%) at checkout when shipping to the UK (I asked Coffee Sensor if they can do the same and take VAT off for UK but they said no). I bought from Blue Star Coffee expecting to pay VAT when it arrived, but it just came at my door with nothing more to pay so got quite a bargain.

Unfortunately it's currently out of stock. However, they might have more on the way and in the last two years had sitewide 10% off on Black Friday, so might be worth asking.


----------



## Bicky

You can also get it here - https://www.theespressoshop.co.uk/en/Coffee-Sensor-Flow-Restrictor-Conversion-Kit-For-E61-Groupheads/m-5028.aspx

Currently out of stock but I contacted them last week and they said they expected to get them back in 2 - 3 weeks. That would have been my preferred option, but I'm impatient :classic_smile:


----------



## natdev34

Thanks @Bicky @Doram. Hopefully I'll be as fortunate!


----------



## woodbar

Would like to get a flow control kit for my MaraX.

I have discounted the Lelit version as it is just too expensive when you include the manometer and handle - I don't want wood anyway.

So it seems that just leaves the Coffee Sensor version, which no-one has in stock at the moment.

I see there is a Profitec/ECM version - is this the same and likely to fir the MaraX?


----------



## prezes

@woodbar I will be selling by coffee sensor kit which I owned since beginning of August this year. Only selling as love it but wanted to complete the wood look so bought the Lelit kit. It will be advertised in the for sale section soon

answering your question the ECM will fit Mara as well


----------



## Bicky

I bought mine directly from Coffee Sensor, looks like they have it in stock. It was dispatched next day and I think took 3 days to arrive.


----------



## prezes

Have been using the Lelit kit instead of coffee sensor for a day and feels so much different. The flow seems to be restricted only slightly moving the paddle. 
Is this right or something wrong with my kit? I measured the flow using two methods. The paddle is fitted so there's no flow when to the left.

*Over 20 seconds from first drip*

full open - 98 + 100.3 + 99.3 = 297.3 / 3 = 99.2 / 20 = 4.96ml/s

3/4 open - 83.1 + 89.4 + 90 = 262.5 / 3 = 87.5 / 20 = 4.375 ml/s

1/2 open - 90.8 + 84.4 + 90.2 = 265.4 / 3= 88.4 /20 = 4.42 ml/s

1/4 open - 71.6 + 77.5 + 78.5 = 227.6 / 3 = 75.8 / 20 = 3.79 ml/s

*Over 25 seconds from start of the pump *

Full open - 119 + 120 + 119.5 = 358.5 / 3 = 119.5 / 20 = 5.9 ml/s

3/4 turn - 117 + 116.8 + 117.6 = 351.4 / 3 = 117.1 / 20 = 5.85 ml/s

1/2 turn - 110.5 + 111.6 + 108 = 330.1 / 3 = 110 / 20 = 5.5 ml/s

1/4 turn - 98.2 + 98.1 + 98.9 = 295.2 / 3 = 98.4 / 20 = 4.92ml/s

photos of paddle positions used as 1/4, 1/2 , 3/4


----------



## Rob1

I'm assuming that's 1/4 open in the second picture not full closed.....


----------



## prezes

Sorry didn't upload them in the right order obviously, so:

3/4 open , 1/4 open , 1/2 open


----------



## kico

Hi,

I just saw this video by lelit insider suggesting we should remove the lower spring at the bottom of the OPV when installing the water flow kit to a Mara X (even if we have the stronger spring installed above it).

**I'm not very technical with it comes to these coffee machines**






I have the coffee sensor flow control kit and have been using it very very very happily since Nov 2020.

I did change the stronger spring, but left the other spring (the video states I should remove it as the bianca does not have one).

I have also completed the water waste reduction mod, removing the water filter and filtering back the unused water back to the tank. This worked before with both springs in, and no water was running out of the OPV during coffee extraction.

I removed the spring and the other component as pictured.

Now when I pull any shot, as soon as it builds up pressure - the water starts trickling out of the OPV. Prior to the flow control and water reduction mod the excess water just trickled into the drip tray from the bottom of the machine. I see a similar waste to before with the flow control, second spring removed, and water reduction mod.

A lot more water also shoots out of the OPV once I push the lever back shut (just as it was before), this seems to be bypassing the water saving mod...

Should I revert it back and pop the spring and component in the attached picture back?

Please see my video attached!

@DoramFYI
@DavecUK Any thoughts please? Thanks!!

















View attachment 2110684919_MaraxVideocompressed.mp4


----------



## Doram

kico said:


> I did change the stronger spring, but left the other spring (the video states I should remove it as the bianca does not have one).


 Thank you very much @kico for tagging me! I did exactly the same as you (replaced the top string for the stronger one that came with the flow control kit, but wasn't aware that the bottom pre-infusion spring and valve should also be removed, so left them in). I will now try to remove the bottom spring and valve and see what happens, though the fact your machine is dripping when the pump is on isn't reassuring. Does it only do that against a blind filter, or during a normal shot as well? I am also interested to hear from Dave if this is normal or not.

I have to say this might be the answer to something that has puzzled me: When I replaced the stock spring with the stronger one that came with the flow control device I expected the slow ramp-up of pressure to disappear, but I didn't notice it did (seemed to ramp up slowly just as before). It confused me, but now I am thinking - maybe leaving the bottom spring and valve we actually didn't do anything to the pre-infusion. This would explain some things...


----------



## kico

Doram said:


> Thank you very much @kico for tagging me! I did exactly the same as you (replaced the top string for the stronger one that came with the flow control kit, but wasn't aware that the bottom pre-infusion spring and valve should also be removed, so left them in). I will now try to remove the bottom spring and valve and see what happens, though the fact your machine is dripping when the pump is on isn't reassuring. Does it only do that against a blind filter, or during a normal shot as well? I am also interested to hear from Dave if this is normal or not.
> 
> I have to say this might be the answer to something that has puzzled me: When I replaced the stock spring with the stronger one that came with the flow control device I expected the slow ramp-up of pressure to disappear, but I didn't notice it did (seemed to ramp up slowly just as before). It confused me, but now I am thinking - maybe leaving the bottom spring and valve we actually didn't do anything to the pre-infusion. This would explain some things...


 That's okay. I have only tried with a blind basket. Won't make another coffee now until tomorrow afternoon but I do not see it performing any differently with actual coffee as the blind basket does replicate full pressure.
I think the higher tension spring did speed up the preinfusion but it never completely stopped it. Removing the second spring has not removed the pre infusion, if anything it feels a little bit like how it was before - slower.

I am tempted to just pop it back how it was, it has been working okay for a year now. Maybe the lelit insider engineer made a mistake?


----------



## MediumRoastSteam

@kico - it feels to me the safety mechanisms of the E61 group have been triggered to protect your machine.

are you sure you installed the correct spring?


----------



## kico

> 1 hour ago, MediumRoastSteam said:
> 
> @kico - it feels to me the safety mechanisms of the E61 group have been triggered to protect your machine.
> 
> are you sure you installed the correct spring?


 That doesn't sound too good, but thank you

100% certain I used the coffee sensor spring in the box (only came with the one).

The effort required at the time to screw it back with all of that resistance is something that still gives me the shivers....

I checked the box again just to be sure and yes, there is only one old spring left.

I popped everything back to how it was and it's performing properly again.

Maybe someone else can check to see if lelit made an error. @Doram


----------



## Rob1

Doesn't look like Lelit made a mistake.


----------



## DavecUK

kico said:


> View attachment 60340


 Please, please use these.....with the jaw covers. The Amazon one below has them not pictured and plenty on ebay etc.. Mine go under the name Amtech. To use them it's important to close them up fraction tight, then push them onto the nut, this allows slack in the mechanism to be taken up and a little give in the jaw covers to be absorbed. this prevents things slipping within the jaws when using.

https://www.amazon.co.uk/Amtech-Adjustable-Pipe-Wrench-Am-Tech/dp/B0186JUOA2










P.S. I actually have 3 of these, so I can always lay my hands on one.


----------



## MediumRoastSteam

kico said:


> Maybe someone else can check to see if lelit made an error


 I agree with @Rob1. Why do you say Lelit made an error? It's more likely the CoffeeSensor spring provided is not as strong as required. As you said yourself, with Lelit's springs there's no leak.

I also added the link to the longer version of that video. It's in Italian, but very easy to follow.


----------



## Doram

kico said:


> Maybe someone else can check to see if lelit made an error. @Doram


 I am confident Lelit didn't make an error. They explained it and it makes perfect sense: the bottom spring and valve are part of the auto pre-infusion system on the Mara X. If you want to replace it with manual control via the flow control device, you need to remove it (to make it similar to the Bianca set up). This also corresponds with my personal experience: I tried to control pre-infusion with the flow control device but felt that the auto pre-infusion hasn't gone away. I was confused by this, and now I know why - it's because I didn't remove it completely.

I only made one cup of coffee (and tried to film while I was at it, so couldn't pay full attention), but I already think I saw that now I have control over pre-infusion that I didn't have before (closing the tap immediately had an effect on the pressure, which wasn't the case before removing the smaller bottom spring).

You can see in the videos below that there is a discharge of water against a blind filter (same as yours), but not during a real shot of coffee. I believe this is expected behaviour.

EDIT: After watching the video uploaded by @MediumRoastSteam (thank you!), it is as clear as day: the dripping of water against a blind filter is a protection feature to prevent too much pressure building up in the group. It's a design feature and it's working perfectly, making the Mara X a little Bianca sister. If you don't remove the bottom spring @kico, you are removing this protection feature and putting your group at risk. From what they show in the video, you *should not* operate the flow control device with the bottom spring and valve not removed!


----------



## MediumRoastSteam

@Doram , @kico - now that I watch he videos again, it feels to me the spring provided by CoffeeSensor is designed for approx. around 9-10 bar pressure. Any more than thet and it compresses, allowing water to be discharged.

the E61 pre-infusion spring is not strong. It's designed to compress at approx 3-4 bar, so with a rotary pump the puck doesn't get slammed right away. It then also have a much stronger spring at the exhaust valve which holds things up to a much higher pressure (don't know how much it can sustain).

if you then remove the exhaust valve components, you'll see water just leaking through the E61 exhaust around 4 bar. So CoffeeSensor provides you with a spring stronger than 4 bar, but, as per my conclusion after digesting all of this, not strong enough to go above 9 or 10 bar.

@kico - try adjusting your OPV (inside the machine) down 1/4 or over, so it is slightly less than the spring and technically you won't see this happening anymore (I think). The water instead will end up in the drip try or, if you have done the mod (which you have) will end up back in the inlet of the pump. 👍


----------



## kico

Than you all! I'll adjust the opv inside the machine soon, but I never take it over 8 bars of pressure /with the flow control)

Removed both parts again as per the video.

See video attached**

I tried it with coffee in this time, a very light Kenyan roast that I've just had delivered. Started the timer early, but I did a very slow extraction lungo with a taper down at the end (triple shot 21.3g in, 70g out.

Sped it up so it would fit. There are no trickles at the start, only just at the end after it's been at 8bar for 20 seconds (but barely any).

/monthly_2021_10/1530295048_VID-20211017-WA00031.mp4.d7c29b55c32aa5ffe1677d842d8b10ec.mp4" type="video/mp4">
View attachment 1530295048_VID-20211017-WA00031.mp4


----------



## MediumRoastSteam

@kico - find out, with both stock springs.

- what's your OPV set to? (Watch the manometer at the machine and the group manometer. They should tally up). Use a blind basket to check that.

Then set that to 9 bar or 9.5 bar.

Then install the spring from coffee sensor and test it out.


----------



## MediumRoastSteam

@kico - I watched the video a few times.

the pressure on the machine gauge reads 9.5 bar. This must be the pressure the OPV is set.

you then control the flow - not the pressure - to allow more or less water through the needle valve. The pressure reads 8 bar on the group gauge. This must mean:

- the pressure between the needle valve, due to the restricted flow, is 9 bar. Read as the water being "backed up" between those two points.

- then, the pressure around the group is 8 bar, and, if the the group is dripping, it must be letting the spring compress, meaning that the spring can only take 8 bar or thereabouts. (This is with coffee flowing, so might be different behaviour than with a blind filter).

I need to re watch the video you did initially. What's the maximum pressure you ever read on the coffee sensor gauge with a blind basket?

edit: watched it. Hard to see, but it seems just above 9 and below 9.5 bar or thereabouts.


----------



## kico

MediumRoastSteam said:


> @kico - I watched the video a few times.
> 
> the pressure on the machine gauge reads 9.5 bar. This must be the pressure the OPV is set.
> 
> you then control the flow - not the pressure - to allow more or less water through the needle valve. The pressure reads 8 bar on the group gauge. This must mean:
> 
> - the pressure between the needle valve, due to the restricted flow, is 9 bar. Read as the water being "backed up" between those two points.
> 
> - then, the pressure around the group is 8 bar, and, if the the group is dripping, it must be letting the spring compress, meaning that the spring can only take 8 bar or thereabouts. (This is with coffee flowing, so might be different behaviour than with a blind filter).
> 
> I need to re watch the video you did initially. What's the maximum pressure you ever read on the coffee sensor gauge with a blind basket?
> 
> edit: watched it. Hard to see, but it seems just above 9 and below 9.5 bar or thereabouts.


 The needle does dance a bit on the coffee sensor after 8.5.

I REALLY do not want to put the stock spring back, I will do what Dave suggested and turn it back 1/2 or maybe even 3/4 as I feel as though the OPV is far too high. It was showing at just above 10 bars on the machine gauge with stock springs, with a blind basket.

Thank you so much for looking in my videos and explaining!


----------



## MediumRoastSteam

MediumRoastSteam said:


> @kico - try adjusting your OPV (inside the machine) down 1/4 or over, so it is slightly less than the spring and technically you won't see this happening anymore (I think).


 @kico - I think that was me. 😉


----------



## DavecUK

@kico Put the E61 vent spring back in as well.


----------



## MediumRoastSteam

DavecUK said:


> @kico Put the E61 vent spring back in as well.


 Won't that go against what kico is trying to achieve, I.e.: to follow the advice from Lelit Insider to not have the vent spring as it causes due strain on the cam pins? 🤷‍♂️

But I agree - put the vent spring back (and the coffee sensor spring, effectively disabling pre-infusion chamber) and it's problem solved as far as venting through the E61 vent is concerned. 👍


----------



## kico

I adjusted the OPV - turned it maybe 1 full rotation, now on the machine the gauge doesn't exceed 9 bar (just over) with a blind basket.

The same goes for extraction, but the coffee sensor gauge maxes out at just over 8bar during extraction.

The vent spring is out, but on this last run there are only tiny drips throughout the extraction.

Even with the blind basket, and the flow valve open all the way, the same amount of drips remain (coffee sensor shows 9 with a blind basket).

See video

This roast is a headache to dial in, I am using a 22G VST.... Lowering the grind makes it choke the machine, and 23.1g still feels like it is too bright (with my calibrated force tamper and RDT tool).

Maybe that's the roast and not me.

Are you suggesting I pop both of those parts back now, insted of keeping them out?

@MediumRoastSteamit seems preinfusion has now been disabled without the spring, and just adjusting the opv down to 9 with the blind basket. There is no ramp up anymore.

View attachment 1898569843_Maraxvideonewcompressed.mp4


----------



## MediumRoastSteam

@kico - it's hard to get the full picture because your videos don't show everything. For instance, I see the needle wobbling, but I have no idea what you are doing with the needle valve.

anyway, I sent you a PM.


----------



## Doram

kico said:


> Are you suggesting I pop both of those parts back now, insted of keeping them out?


 @kico - here is an extract from Dave's review of the Lelit FC kit. You can see that it's the same as the video from Lelit, and shows the lower spring and valve should be removed:











DavecUK said:


> @kico Put the E61 vent spring back in as well.





MediumRoastSteam said:


> But I agree - put the vent spring back


 @DavecUK, @MediumRoastSteam - can you please clarify what is the vend spring that needs to be put back?


----------



## DavecUK

@Doram the bottom one


----------



## Doram

DavecUK said:


> Doram the bottom one


 I am confused: isn't the bottom one the one you (and Lelit video) say to remove?


----------



## DavecUK

He is not using the Lelit kit though.

Clearly in the Lelit E61 group the preinfusion spring replacement from the coffee sensor kit isn't strong enough, assuming it's installed correctly. If it was, there wouldn't be a leak from the group vent, which he keeps cofusingly calling the OPV.

Adding the vent spring back won't make any excess pressure on the cam. Will stop it leaking an the preinfusion effect will still be made minimised.


----------



## Doram

DavecUK said:


> He is not using the Lelit kit though.


 I see.

So what is the difference between the function of the Lelit and the Coffee Sensor flow control kits? They both add a needle valve and replace the stock pre-infusion spring with a stronger one to disable pre-infusion, right? So why does the Lelit kit need the vent valve removed and the Coffee Sensor kit needs it installed?


----------



## DavecUK

@Doram Because the Lelit spring replacement in the Lelit group does hold more than 9 bar. I was adding to the above post, slowly cos on phone.


----------



## Doram

DavecUK said:


> He is not using the Lelit kit though.
> 
> Clearly in the Lelit E61 group the preinfusion spring replacement from the coffee sensor kit isn't strong enough, assuming it's installed correctly. If it was, there wouldn't be a leak from the group vent, which he keeps cofusingly calling the OPV.
> 
> Adding the vent spring back won't make any excess pressure on the cam. Will stop it leaking an the preinfusion effect will still be made minimised.


 Thanks very much for clarifying this Dave, much appreciated.

For me (and I think for @kico as well), the leak from the group vent is limited to running the pump against a blind filter. I don't have any such leak when running a normal shot (with the stronger spring from Coffee Sensor and the vent spring removed.

Because Lelit's video showed what seems like exactly the same leak when running against a blind filter, I thought that this is exactly as intended (protection feature) and the Coffee Sensor FC works exactly the same as the Lelit FC. So if Lelit recommends removing the vent spring for theirs, then this should be the same for Coffee Sensor.

*However - the plot thickens...*

I wanted to be 100% sure so asked both Lelit and Coffee Sensor about this today, and have already received answers.

Lelit didn't want to know. They just told me to ask my retailer. Fair enough, but obviously unhelpful.

Coffee Sensor's answer is interesting though. Not only did Tudor say the vent spring doesn't need to be removed, he also said that for *reservoir-fed machines* (as opposed to plumbed machines) the upper pre-infusion spring *should not* be replaced with the stronger spring that comes in the FC kit.

This is how he explained it:

"If you have water reservoir, that would have a small impact over flow control, since the oem pre infusion on those machine is mild. I would use it WITHOUT the new stronger spring. That one is best with plumbed machines since the pre infusion at those is way higher, at water network pressure, which is usually all the way to 3.5 bar. OEM pre infunsion ca be a max 1 bar. But usually too mild top bother with the stronger spring."

I may be wrong about this, but doesn't that mean that on a reservoir machine like Mara X we are 'stuck' with the built in pre-infusion? Would love to know what you make of this @DavecUK.


----------



## MediumRoastSteam

Doram said:


> Would love to know what you make of this


 I thought OEM spring is set to 3-4 bar. Hence why you often see a small delay in the pressure build up around 3-4 bar? I don't think it's 1 bar.

If you keep the OEM spring and remove the stronger vent spring at the bottom... You'll never go above 4 bar as the water will just run into the drip tray around 4 bar. That's a great way to test the strength of the spring, in fact 🙂

---

As for the argument around mains pressure... It only has any importance if you use the "mid position" on the E61 and want to pre-infuse at mains pressure. So, with the pump running, the pressure from a plumbed in machine or tank fed machine will be eventually the same. So I don't really get the argument. But maybe I'm missing something. And with a rotary machine it will build the up the pressure significantly faster compared to a vibe pump.

---

When Tudor say OEM pre-infusion... If you run the pump, the brief built-in pre-infusion of the E61 (That's OEM as far as I understand) it will effectively pre-infuse at 3-4 bar for 1 or 2 seconds (the water pressure will build up against that seat/spring, will eventually compress the spring at 3-4 bar until the chamber fills up) and then carry on building until either the OPV spring compresses at around 9.5-10 bar (or whatever you set it to) or the coffee puck saturates and water starts coming out from there.


----------



## Doram

MediumRoastSteam said:


> I thought OEM spring is set to 3-4 bar. Hence why you often see a small delay in the pressure build up around 3-4 bar? I don't think it's 1 bar.
> 
> If you keep the OEM spring and remove the stronger vent spring at the bottom... You'll never go above 4 bar as the water will just run into the drip tray around 4 bar. That's a great way to test the strength of the spring, in fact 🙂
> 
> ---
> 
> As for the argument around mains pressure... It only has any importance if you use the "mid position" on the E61 and want to pre-infuse at mains pressure. So, with the pump running, the pressure from a plumbed in machine or tank fed machine will be eventually the same. So I don't really get the argument. But maybe I'm missing something. And with a rotary machine it will build the up the pressure significantly faster compared to a vibe pump.
> 
> ---
> 
> When Tudor say OEM pre-infusion... If you run the pump, the brief built-in pre-infusion of the E61 (That's OEM as far as I understand) it will effectively pre-infuse at 3-4 bar for 1 or 2 seconds (until the chamber fills up).


 Thanks for this. I am just getting more and more confused. What is the bottom line then? What springs should be changed/kept/removed? What information is correct and what isn't? Can't life be just a tiny bit simpler? 🤣


----------



## MediumRoastSteam

Doram said:


> Can't life be just a tiny bit simpler


 Nope. Springs are here to complicate your life. 🤣🤣🤣🤣🤣🤣

to be honest, I haven't got the faintest idea of what's right and what's wrong. Personally, I don't think there's a right or wrong - it's about what you want to achieve. Let's face it, if you leave the seeing's in place and just change the top valve, you can't damage the pins. What the difference between the flow profile open fully and no flow profile? The pressure exerted on the cam pins is the same. Unless you go below 4 bar when profiling, replacing the pre-infusion spring makes no difference, as far as I understand.

If you don't want leaks on the vent, having CoffeeSensor spring to disable OEM pre-infusion and keep the original vent spring on will do the trick if you want to go above 10-11 bar without venting though the group. I'm not sure what's the resistance of the vent spring, but presumably higher than 12 bar.

The only reason that I can think of of having those springs fitted and the vent spring removed is so that that's the maximum pressure tolerated by the valve in the respective flow profiling kits.


----------



## woodbar

Doram said:


> Lelit didn't want to know. They just told me to ask my retailer. Fair enough, but obviously unhelpful.


 Hmm, I asked them twice for the adjustment range specification of the OPV valve on the MaraX and got the same reply - plus finished with -

We remain at your complete disposal for any issue, thanks and best regards

I don't think so!

I am waiting for my Coffee Sensor kit to arrive and I was intending to leave the PI and exhaust arrangement OEM for the moment which sounds like it might be a sensible idea in view of the problems above


----------



## prezes

Funnily enough I emailed Lelit support regarding my issue and to comment on compatibility of their flow valve and MaraX. What do I get back ?

Hello, thank you for contacting us and for using a LELIT MaraX coffee machine. Please note that any modification on the product without the authorization of the reseller means voiding the warranty. Also the installing of the flow control valve has to be following your reseller's instruction. Therefore we kindly ask you to contact your reseller as your machine should be under warranty. We remain at your complete disposal for any issue, thanks and best regards


----------



## Doram

prezes said:


> Funnily enough I emailed Lelit support regarding my issue and to comment on compatibility of their flow valve and MaraX. What do I get back ?
> 
> Hello, thank you for contacting us and for using a LELIT MaraX coffee machine. Please note that any modification on the product without the authorization of the reseller means voiding the warranty. Also the installing of the flow control valve has to be following your reseller's instruction. Therefore we kindly ask you to contact your reseller as your machine should be under warranty. We remain at your complete disposal for any issue, thanks and best regards


 I don't understand what you are complaining about - it's totally consistent:

Any modification you do will void your warranty, so please follow the instruction when modifying your machine to keep the warranty.

Springs and valves must be removed and replaces for the machine to function, so don't remove or replace them to keep the machine functioning.

If anything isn't clear - ask someone else. However, please don't hesitate to ask us again.


----------



## woodbar

Yes, it seems a very consistent -

"Don't bother asking us, we only manufacture the machines and we can't offer any information on an accessory that we offer and list on our website as compatible/suitable with the MaraX. Your reseller must be consulted on all matters relating to this equipment but we are always available to reply with a standard GO-AWAY response should you feel the need to contact us again"

To be honest it does not surprise me - in my former life as a Technical Manager for a global commercial laundry equipment manufacturer we acquired two factories in that particular country that produced finishing equipment for us - steam presses and steam cabinets etc. Getting technical, repair and service information from them was a nightmare.

We even had several instances where we installed multiple items of the same model machine on site, ordered and delivered at the same time, only to find that they had differing internal components and did not correspond to the spares/commissioning/service info actually provided with them!

*Così è la vita!*


----------



## MediumRoastSteam

I'll buck the trend: When I contacted Lelit with an issue I had, they were extremely helpful and helped me track things down. Presumably they are doing their due diligence as, if the user then breaks the machine because they want to install an accessory and the user then claims under warranty, the responsibility of the warranty is with the reseller, not with Lelit. Can you imagine if then the user says "But I emailed Lelit and they said it was OK...."

I would even go as far as saying they are doing the sensible thing whilst the machine is under warranty. I bet the response would be different if you said the machine was not under warranty. 🙂


----------



## woodbar

So, is your machine you had the problem with out of warranty?

Of course it could just be down to the particular CS agent you get and how many espressos they have had today!


----------



## Doram

MediumRoastSteam said:


> I bet the response would be different if you said the machine was not under warranty. 🙂


 They might say you should put the machine over the warranty. 😉

Seriously though, I also had good service from Lelit in the past, and in this instance thought it was fair that they didn't want to comment on the Coffee Sensor flow control device as it's not made by them and they can't take responsibility. It would be nice of them to try to help, but I completely understood why they didn't want to.

Given the conflicting opinions (pre-infusion spring should be replaced with a stronger spring / shouldn't be replaced on a non-plumbed machine; vent spring should be removed / it should be kept in), and as in my own experience the flow control device worked fine in all spring combinations, I will conclude (for now) that all those combinations are safe to use and will just experiment and see what works for me. I am honestly not sure I can tell the difference to be honest, so maybe this is much fuss about nothing? I don't know.


----------



## DavecUK

OK, lots of stuff in various posts, plus misinformation based on a lack of knowledge. here are some facts

1. If you have a spring which is tensioned to say 9 bar and the cam pin presses on it by moving the lever, your pressing against 9 bar...when you get the second spring, the first exterts 9 bar on it and you need an extra 4 bar for the pin to press on the lower spring (if the lower spring is set to 13 bar, it could be 12, or 11.5 depending on group and machine)









So you won't wear the cam pins any more than if you had the normal preinfusion spring in.

2. The lower vent spring is much shorter and the modulus is not really linear in these springs. The preinfusion spring is dimensionally longer and it's tricky to make a spring that exerts 10 bar without getting overly stiff as it compresses to move the vent spring

3. The preinfusion spring letting by won't affect the shot so much as it will flatten out the chamber fill....so if the vent spring is in place, at the expense of a little volume of water filling the spaces, it will stop the dribble from the vent, IF you find it a problem

4. Whether the machine is run from the tank or mains is irrelevant

5. The effect of the preinfusion chamber will be more noticiable on a vibe pump compared to a rotary (where the water debit is so high, it doesn't do much). In fact it might be argued that on a rotary, the filling of the preinfusion chamber, might cause a small water hammer effect.

6. Solenoid groups seem to work fine with rotarys or vibes and no preinfusion chamber

7. Preinfusion chambers slightly confused computerised profiling machines...but not a man with a paddle.


----------



## kico

DavecUK said:


> He is not using the Lelit kit though.
> 
> Clearly in the Lelit E61 group the preinfusion spring replacement from the coffee sensor kit isn't strong enough, assuming it's installed correctly. If it was, there wouldn't be a leak from the group vent, which he keeps cofusingly calling the OPV.
> 
> Adding the vent spring back won't make any excess pressure on the cam. Will stop it leaking an the preinfusion effect will still be made minimised.


 I am less confused now, thank you. I'm not very technical / maybe I should've just bought the decent 😂



DavecUK said:


> @Doram Because the Lelit spring replacement in the Lelit group does hold more than 9 bar. I was adding to the above post, slowly cos on phone.


 That makes more sense

@MediumRoastSteam@Doram
I think I'm going to pop in the bottom spring and continue with how it was before.

Still, I'm glad that I purchased the coffee sensor kit instead instead of the Lelit one as I don't like the wooden paddle.

I would 100% recommend it, as I haven't had any issues in the past year.

Thank you all for your input, and sorry for starting this mess!


----------



## DavecUK

@kico Don't apologize, it's an interesting discussion.


----------



## Bicky

I recently got the Coffee Sensor FCD and I replaced the bottom spring. As far as I can tell it's working perfectly and I think there's definitely a difference in the time to pressure ramp up between the stock spring and the new one, *when the FCD is in the fully open position (stock flow rate)*.

Before I got the FCD I watched this, and they do the same -


----------



## MediumRoastSteam

Bicky said:


> I think there's definitely a difference in the time to pressure ramp up between the stock spring and the new one,


 There should be - with a strong spring above 10 bar or so, you are effectively removing the pre-infusion chamber. Less space to fill up, therefore less time to pressure.


----------



## Bicky

MediumRoastSteam said:


> There should be - with a strong spring above 10 bar or so, you are effectively removing the pre-infusion chamber. Less space to fill up, therefore less time to pressure.


 If you say so, all I know is it was a complete PITA to get on :classic_laugh:

It does mean that, assuming you want some sort of pre-infusion, there's always going to be some manual adjustment of the FCD required. If you're happy with the stock pre-infusion and only want to control flow during the extraction stage, then I guess leave the stock spring in. You have less direct control over pre-infusion, but you can get that gentler ramp up without any manual intervention on the FCD.


----------



## Doram

Bicky said:


> If you say so, all I know is it was a complete PITA to get on :classic_laugh:


 Did you lift the lever while trying to screw the bottom of the group on? I vaguely remember this made it a bit easier.



Bicky said:


> It does mean that, assuming you want some sort of pre-infusion, there's always going to be some manual adjustment of the FCD required. If you're happy with the stock pre-infusion and only want to control flow during the extraction stage, then I guess leave the stock spring in. You have less direct control over pre-infusion, but you can get that gentler ramp up without any manual intervention on the FCD.


 Maybe I am wrong about this (still learning), but isn't it true that you can always slow down pre-infusion by restricting the flow (even with the stock spring and slow ramp up)? The stock string would only stop us from having a *shorter* pre-infusion, won't it? And would we ever want a shorter pre-infusion than what is offered by the stock spring and slow ramp up?

Don't get me wrong: I am using the Coffee Sensor FCD with the stronger spring just like you an @kico. I am just trying to figure out what's going on.


----------



## DavecUK

@Doram With the lever in the 45 degree angle position then the pressure on the top group valve and preinfusion valve is at a minimum, it should make it easier to screw the preinfusion chamber on.

It's also the easiest position to jiggle the lever/cam in and out for greasing.


----------



## Bicky

Doram said:


> Did you lift the lever while trying to screw the bottom of the group on? I vaguely remember this made it a bit easier.


 Honestly can't remember, only that trying to push it up and screw it on at the same time wasn't easy!

As for using the stock spring, yes you can still control pre-infusion, that's why I said *less direct control*. Why? I don't know, Turbo shots? My point is that it's another factor to consider if you are say, trying to copy some flow profile, or guidance, like use X flow rate until you see first drops, because you might see those first drops at a very different time from me if you have this extra chamber to fill....

Maybe none of this matters! Maybe these things change from machine to machine, brand to brand anyway? These are just my thoughts based on my limited knowledge, just like you, I'm still learning 😃. Changing the spring however, in my mind, takes this additional factor away when thinking about this stuff.


----------



## prezes

I've been back on forth with Lelit trying to get some help and got a link back this evening. May throw some light into the spring in or out query.


----------



## MediumRoastSteam

> 40 minutes ago, prezes said:
> 
> I've been back on forth with Lelit trying to get some help and got a link back this evening. May throw some light into the spring in or out query.


----------



## prezes

MediumRoastSteam said:


> Errr&#8230;. Back and forth? Looks like we've gone full circle!
> 
> on Saturday, @kico started all of this&#8230; showing us a link to this very video! 😂😂😂😂😂🤣🤣👍👍👍👍
> 
> https://www.coffeeforums.co.uk/topic/56566-lelit-mara-x-flow-control-kit/?do=embed&comment=860275&embedComment=860275&embedDo=findComment


 Ignore me !!! I've missed this post somehow !


----------



## prezes

I'm loosing the will to live with this ! Set the opv to 9.5 bar yesterday and been pulling shots with both gauges not exceeding 9.5 bar.

after Lelit's reply this evening I changed the spring to stronger one and removed the bottom spring. No other changes made and both gauges get up to 10.5 bar. Am I missing something ?


----------



## MediumRoastSteam

prezes said:


> Set the opv to 9.5 bar yesterday and been pulling shots with both gauges not exceeding 9.5 bar.


 Which spring was in there? Coffee sensor or the original MaraX?

edit: I'm also losing it&#8230; I can't remember if it's you @prezes or @kico who have both kits!


----------



## prezes

I had the coffee sensor and replaced it with Lelit kit. Was using stock Lelit MaraX spring till this evening


----------



## MediumRoastSteam

I have no idea. The only thing I can think of is that, because with the much weaker, stock spring + vent spring, the pre-infusion chamber will open and therefore you have more space to fill, which could influence the reading. I have no idea. Whereas, with the stronger spring from the Lelit kit, that chamber is effectively disabled and never fills up.

All speculation, I have no idea.


----------



## woodbar

I have just installed the Coffee Sensor FDC on my MaraX and it does seem to "do what it says on the tin" from my first few tries with it - had to change beans half way through so that complicated things a bit!

I did not make any changes to the PI or dump valve springs in the lower section as, for the moment at least, I like the safety of the extended PI that the Lelit provides.

This was a slightly used pre-owned kit and I decided to remove the mushroom to check and lubricate the O rings before I fitted it. To my surprise a complete circle of part of the lower O ring just fell out leaving about three quarters of the original in place!

Obviously I cleaned and greased everything and fitted one of the spare O rings - actually the top one looked a bit "swollen" but I thought it would be serviceable for a while as I did not want to use up both of the spare ones as I think the lower O ring might be problematic!

The reason - to me I think this FDC has a major design flaw - when you close off the needle valve the lower seal is extended completely from inside the top spindle sleeve and exposed to hot high pressure water on all sides and you are relying on only the top O ring to provide the seal. When you start to open the valve, at about half a turn or so, the lower O ring gets pulled back up into the housing and although this has a chamfered orifice entrance it only needs to slightly catch on the O ring and that's it - your O ring is toast!

You can actually feel the increased resistance to the turning motion of the handle as you open the valve up - and conversely a lightening of resistance when closing it down - as you change from 2 O rings in the sleeve to just the 1 upper one.

I think they should have made the top housing taller which would have allowed for a slightly longer adjustment spindle and the retention of BOTH O rings within the spindle sleeve at ALL settings of the valve?

As it is, it works, but I need to find a ready supply of replacement O rings for regular inspection and replacement. Just need to sort out the size and specification?


----------



## woodbar

@prezes I have been following this thread with interest and I might have had a "eureka" moment (or not!).

It seems that your Lelit kit is not adjusting the flow much and still ramps up to full OPV pressure on the head manometer when pulling a shot at most settings of the FCD?

If that is the case then logically maybe the taper pin is not actually getting inserted into the brass jet?

Simple questions -

1) Did you fit the new brass jet? I am sure you did but just covering every possibility.

2) Did you wind the shaft Up as high as it will go before fitting the assembly - if not you could have possibly bent the needle and it is now not entering the hole in the brass jet?

3) Have you tried the spare jet?

Just my thoughts!


----------



## prezes

@woodbar Thanks a lot as all the ideas are welcome to get to the bottom of it.

1) I've fitted new brass jet.

2) the shaft was wound up all the way before inserting. I removed and re-fitted again since and it's definately not damaged and in the jet.

3) haven't tried spare jet.

The issue is that moving the paddle between the fully open position and near closed makes almost no difference. It only reacts when almost closed position which adjusts the group pressure gauge to about 8 bar or just under.

Running the flow test just shows this as well it only reduces flow by around 1ml/s between fully open and 1/4 open position.

Mind boggling!


----------



## Doram

woodbar said:


> As it is, it works, but I need to find a ready supply of replacement O rings for regular inspection and replacement. Just need to sort out the size and specification?


 If you find the correct O rings and/or their specification - please share. 🙂

I have also seen some damage to the O ring on mine when I first opened to lube it. Didn't change it because damage looked minor and I didn't want to waste an O ring if I could help it. Since then I avoided fully closing and fully opening the valve (not a problem for me), and hopefully didn't stress the O ring so much (it seems to be working fine and I don't feel the changes in resistance, which hopefully are good signs). I will know more the next time I open it up to lube again (holding it off for now, as if works and feels nice and smooth).


----------



## woodbar

Doram said:


> If you find the correct O rings and/or their specification - please share. 🙂


 I have emailed Coffee Sensor asking for the specification so will share any reply.

At least I still have a new spare so I could measure that but not sure what material it is.

It would be interesting to know exactly how many users of this device have found damaged O rings because I think, owing to the design, it will me most!


----------



## woodbar

prezes said:


> The issue is that moving the paddle between the fully open position and near closed makes almost no difference. It only reacts when almost closed position which adjusts the group pressure gauge to about 8 bar or just under.
> 
> Running the flow test just shows this as well it only reduces flow by around 1ml/s between fully open and 1/4 open position.


 OK, well it was worth asking.

Talking of damaged O rings - just another thought - it could be that the main O ring on the mushroom is damaged or not seated properly?

You would have had to re-install the original Lelit one to change from one FCD to the other and I note there are small bypass holes around the jet fixing which feed through to the mushroom chamber?

So, if the FCD valve is closed BUT the main mushroom O ring is damaged then pressurised water could bypass the FCD around the outside of the mushroom?

Not totally got my head around the workings of the E61 but just a thought?


----------



## woodbar

Re: the small O rings for the Coffee Sensor FCD. Not heard back from CS yet.

I have done a bit of measurement and the size seems to be 6.07mm ID x 1.78mm CS - so the same size as @DavecUK mentioned somewhere to fit the Lelit FCD.

Strange that this is actually an Imperial (UK) size (BS010) and not a metric standard size?

Anyway I have ordered a pack of 10 in Viton material which is supposed to be a tougher material compared to EPDM or Nitrile etc. (so Google informs me!) Of course it might be too "tough" and not want to slip back into the housing without a fight (see my post above)

I will update when they arrive and I have tried them.

Edit: Having done even more research it seems O rings are a science even more complicated than just making Espresso!

I now note that there are a multitude of different grades and specifications within each type of material composition and it is only certain types or grades of Viton that are suitable for hot water/steam!

It would seem that EPDM would be a more suitable choice.


----------



## DavecUK

@woodbar I like FKM, but that's me


----------



## woodbar

DavecUK said:


> I like FKM, but that's me


 As far as I can tell FKM is another name for Viton (and FPM, Fluorel etc.) and it seems Viton is just a generic name - a bit like Hoover for a vacuum?

I have asked the supplier to change my order to EPDM if it's not too late else I will just order another 10 in EPDM - it's only a few quid and it might be good to try both types and see which type survives better.


----------



## bcoffee

DavecUK said:


> @woodbar I like FKM, but that's me


 Genuinely curious why you prefer FKM?

Typically FKM is marketed as being less suitable for hot water/steam than EPDM, are there other factors that make it more suitable in this case?


----------



## woodbar

Could not change my order, only cancel it if required.

Decided to let it stand and also ordered some EPDM versions so I will have BOTH types to try!


----------



## bcoffee

woodbar said:


> Anyway I have ordered a pack of 10 in Viton material which is supposed to be a tougher material compared to EPDM or Nitrile etc. (so Google informs me!) Of course it might be too "tough" and not want to slip back into the housing without a fight (see my post above)
> 
> I will update when they arrive and I have tried them.
> 
> Edit: Having done even more research it seems O rings are a science even more complicated than just making Espresso!


 All 3 of those materials will be available in different grades, so the stiffness of them will largely be dependent on what grade you end up ordering/is available.

Typically, they will be measured by 'hardness', normally Shore A these days. Similar numbers (within 5-10) will be roughly similar, so you shouldn't have any big problems fitting unless they are wildly different numbers?


----------



## woodbar

bcoffee said:


> Typically, they will be measured by 'hardness', normally Shore A these days. Similar numbers (within 5-10) will be roughly similar, so you shouldn't have any big problems fitting unless they are wildly different numbers?


 Yes, as I thought above choosing the specifications for what one might think is a normal O ring is a very deep rabbit hole.

Hopefully I will find one of the versions I have ordered to be more durable than the version the OEM fitted to the FCD but I tend to think it is the design that is a bit suspect rather than the choice of O Ring.


----------



## DavecUK

bcoffee said:


> Genuinely curious why you prefer FKM?
> 
> Typically FKM is marketed as being less suitable for hot water/steam than EPDM, are there other factors that make it more suitable in this case?


 https://trp.co.uk/what-is-the-difference-between-fkm-and-epdm/

remembering that Viton is FKM


----------



## bcoffee

woodbar said:


> Yes, as I thought above choosing the specifications for what one might think is a normal O ring is a very deep rabbit hole.
> 
> Hopefully I will find one of the versions I have ordered to be more durable than the version the OEM fitted to the FCD but I tend to think it is the design that is a bit suspect rather than the choice of O Ring.


 Sadly, I suspect you may be right - although I'm not familiar with the valves - if the part is well designed, I wouldn't expect the o-ring to be in a position to be cut/pinched.

If as I'm inferring from your comment before it is constantly being moved in and out of a hole then it probably doesn't matter too much what the material you use is as you simply can't make a material soft enough to be an o-ring and hard enough to not be damaged by this over time...


----------



## prezes

I've been watching the machine gauge since replacing the spring and removing the bottom spring yesterday's and it looks like the pre-infusion is still in place ? Not sure if the video is clear enough so can do another one if not.


----------



## bcoffee

DavecUK said:


> https://trp.co.uk/what-is-the-difference-between-fkm-and-epdm/
> 
> remembering that Viton is FKM


 Apologies if I'm heading off on a tangent here (feel free to ignore), I'm just interested as I have a background in materials, and am always curious as to how and why choices are made in end products. Whilst I appreciate that you are not a manufacturer, I'm aware you do offer advice to them - and more importantly, real world knowledge!

Viton/FKM is one of those unfortunate catch-all terms which covers a whole bunch of grades of material, whilst the high end (peroxide cured) ones are pretty good for hot water/steam, some of the lower ones are typically rated poorly for this.

In general, I would expect manufacturers to plump for the cheaper EPDM in most instances as it would 'do the job'.

I was interested if you found that they were more susceptible to wear, had other concerns re: cleaning fluid compatibility, or found that the extra temperature resistance was beneficial around very hot parts, e.g. elements?


----------



## Bicky

> 20 minutes ago, prezes said:
> 
> I've been watching the machine gauge since replacing the spring and removing the bottom spring yesterday's and it looks like the pre-infusion is still in place ? Not sure if the video is clear enough so can do another one if not.


 I've largely ignored the gauge on my machine since installing the FCD as I assumed it no longer gave any meaningful reading, and the one on the group seems to directly respond when I change the flow, so I assume it's accurate. I'm now wondering what mine is doing, I'll check tomorrow!


----------



## DavecUK

@bcoffee I have NBR O ring Kits and FKM....I would use either in the flow control valve because it typically doesn't get above 90 - 100C. One of the key things that will help it last is a good fit and regular lubrication. FKM should be the last rubber to harden and I would expect the o rings on flow controls to need replacement within 2 years depending on machine on time. They are not a permanent solution as many people might think.

I have both kits to give me o rings to use in a wide range of applications from Vac breakers to domestic tap parts. I recently use the NBR to fix a Franke kitchen mixer cartridge tap that was leaking at one of the levers (it's usually the hot one and usually within 4 years. 10p or less and 2 o rings and it's good as new. I suppose I could try and find EDPM O ring kit as well...but they are tricky to find, most say rubber or NBR.


----------



## woodbar

bcoffee said:


> If as I'm inferring from your comment before it is constantly being moved in and out of a hole then it probably doesn't matter too much what the material you use is as you simply can't make a material soft enough to be an o-ring and hard enough to not be damaged by this over time...


 Thanks for your input.

Yes, that is exactly what seems to happen and I agree - I think it needs NASA to work on it to get a compatible material to cope!


----------



## woodbar

prezes said:


> I've been watching the machine gauge since replacing the spring and removing the bottom spring yesterday's and it looks like the pre-infusion is still in place ?


 That does seem odd - about 4.5 seconds before the group manometer starts to rise and the pump one is reading about 3.5 - 4 bar.

The pump is bound to need a ramp up time to pressurise the system but you would think they would both start to rise at roughly the same time as long as the FCD is open. I tried this on mine and the group manometer does lag behind slightly but nowhere near this amount.

Did you actually get around to checking the mushroom O ring?


----------



## prezes

@woodbar not yet as at work most of the day will inspect tonight.


----------



## bcoffee

DavecUK said:


> @bcoffee I have NBR O ring Kits and FKM....I would use either in the flow control valve because it typically doesn't get above 90 - 100C. One of the key things that will help it last is a good fit and regular lubrication. FKM should be the last rubber to harden and I would expect the o rings on flow controls to need replacement within 2 years depending on machine on time. They are not a permanent solution as many people might think.
> 
> I have both kits to give me o rings to use in a wide range of applications from Vac breakers to domestic tap parts. I recently use the NBR to fix a Franke kitchen mixer cartridge tap that was leaking at one of the levers (it's usually the hot one and usually within 4 years. 10p or less and 2 o rings and it's good as new. I suppose I could try and find EDPM O ring kit as well...but they are tricky to find, most say rubber or NBR.


 Thanks Dave, I hadn't really considered the difficulties in finding consumer available EPDM ones. I agree, regular inspection and replacement is by far the most effective approach and can often make up for material shortcomings, within reason obviously.

Diversion over 🙂


----------



## woodbar

prezes said:


> not yet as at work most of the day will inspect tonight.


 Sorry, us retired folk keep forgetting about such things😉


----------



## woodbar

More info on the O rings for the Coffee Sensor FCD.

I had a reply from Tudor -



> The small orings can be VITON or silicone, size from outside to inside 10 x 6 x 2. VITON is better in high temp water environment.


 Observations - Viton (unless specially formulated) is generally not recommended for use with Hot Water/Steam and the OD of the spares in the kit is 9.63mm (6.07 + (2x1.78)) as opposed to the 10mm quoted - not much difference - in fact the larger CS might sit better in the lower groove which seems a bit wider than the top one?. Also Silicon tends to have a poor resistance to tearing so I would not even try that formulation here.

I have stripped my FCD again and can definitely confirm that the lower O ring does come fully out of the sleeve when the valve is completely closed. As a result the brand new spare green O ring I fitted approximately 12 coffees ago was already wedge shaped where it has to re-enter the sleeve when you open the valve. Not really impressed with this design I must say - a taller top assembly (with longer shaft) or a higher shoulder on the jet would have stopped this happening.

Having said that I ordered both Viton and EPDM replacement O rings, 6.07 ID 1.78 CS, and the Viton ones arrived so I thought I would give them a try. I only replaced the bottom small O ring with what I understand is an FPM (aka Viton) one. The new one is much less compressible/stretchable than the OEM green variety which I thought might be a problem but when assembled I found the action of the valve considerably smoother throughout its travel!

We'll see. I will give a few days use then have a look to see what state it is in!

Generally the FCD controls the flow/pressure very well and is quite responsive to small adjustments.


----------



## woodbar

I am surprised no-one picked me up on a suggestion I made to @prezes a couple of days ago -



> Talking of damaged O rings - just another thought - it could be that the main O ring on the mushroom is damaged or not seated properly?
> 
> You would have had to re-install the original Lelit one to change from one FCD to the other and I note there are small bypass holes around the jet fixing which feed through to the mushroom chamber? Irrelevant - in any case they "feed the top jet" FROM the external side of the mushroom chamber
> 
> So, if the FCD valve is closed BUT the main mushroom O ring is damaged then pressurised water could bypass the FCD around the outside of the mushroom?


 Perhaps nobody read it! Just a bit of brain fade.


----------



## DavecUK

@woodbar I didn't spot it, but yes I guess that could happen...wouldn't be so notciable normally but with a valve...for sure. Certainly if a Lelit valve where the mushroom is replaced is put into an old group, or when the other type is installed if the o ring doesn't seat properly. It's alo worth considering that when completely closed puts the O ring on the mushroom under extra stress...so it needs to be in good condition.

http://coffeetime.wikidot.com/the-mystery-of-the-e61-group-mushroom


----------



## woodbar

There's more!

Stripped the Coffee Sensor FCD of the MaraX this afternoon to check on the new Viton O ring I installed the other day.









Oh dear! I don't think Viton (FPM) is suitable!

The small sheared off fragment was sitting inside the little filter.

Cleaned it all up - fitted an EPDM replacement - greased as necessary - refitted - works nicely again now but will have a look in a few days😉

To be honest I am not hoping for much as I think the design - where the O ring gets moved out of then inserted back into the sleeve basically every time you use the device - is seriously flawed.

We will see.


----------



## DavecUK

@woodbar Is it very different to the Lelit one..I'm trying to imagineer it unless you have some photos...because the O rings must surely stay in the sleeve during operation?


----------



## woodbar

DavecUK said:


> because the O rings must surely stay in the sleeve during operation?


 NO - they don't!

That's the whole point why I think it is a poor design. Only the top O ring stays inside the sleeve. The lower O ring (that keeps destroying itself) is totally screwed (in more ways than one) out of the sleeve when the needle valve is closed - it does not get pulled back into the sleeve until you open the valve about 3/4 of a turn.

When I check the EPDM one I fitted today I will definitely take some photos.

I did have the idea of trying to put a spacer under the valve, if the thread is long enough as that might just move all the action further up the adjustment range and keep the lower O ring mostly inside the sleeve, but I am a bit reluctant to try unscrewing it as if the brass thread parts company then I will be screwed!

I note one of the suppliers advertising this device says it's the "New 2021 improved version"? I wonder what they improved............?


----------



## woodbar

OK - just had the Coffee Sensor FCD off again to check - the EPDM lower O ring has not done well -









and it managed to spawn a mini EPDM slug inside the filter!

I did think that maybe the O ring could catch on the mesh filter but it cannot as the diameter of the shaft where the O rings sit is just a bit bigger than the filter dimension.

This is how the needle valve looks when it is in the fully closed position -









...and another view









The O ring does not start to enter the bore until you have opened it at least 3/4 turn!

This is absolutely crazy design!

Now, let me say that I bought this kit as a 2 month old used item so I cannot guarantee that it is totally OEM but I have no doubt that it is - especially as others also seem to find this O ring in bad shape when they open up their device!

I will continue in another post showing what I have modified.


----------



## DavecUK

@woodbar *I've lost track of the O ring sizes you are using...*

The Lelit ones are EDPM with an ID of 6.07 and a diameter(thickness) of 1.78

The quoited ones of 10 mm is enough difference to catch on entering the bore and possibly cause problems...have you measured and double checked the sizes?


----------



## woodbar

Just as an add-on to the above - I confirmed the fully closed (no water) position as I had marked the top spindle/housing and removed the valve with it at this setting









Having thought about it for a while I managed to remove the jet in the top of the mushroom and with a bit of DIY I managed to make a spacer to raise the jet a bit so that the needle valve shaft cannot screw down as far as it previously could.

This involved esoteric materials including a brass screw cup (with the hole filed out a bit to fit around the thread on the jet) plus 2 by M6 stainless steel washers to provide support to the back of the screw cup plus a bit more thickness. The jet has a tapered seat so it actually fitted nicely into the screw cup!









There is actually more thread to fix the jet in than you can see here with it just all loosely assembled.

Before modification the jet top surface was 2.6mm below the top of the mushroom - after fitting my spacer it is just 0.5mm below the top - so I have gained approx 2.1 mm less downward travel, to the closed position, of the spindle and lower O ring. Unfortunately this looks like it still might NOT be quite enough as even then the O ring is "almost" out of the top assemble bore! A bit difficult to judge.

I have decided to try it out anyway - heated it up - made a coffee - seemed to work fine - but will have another look inside in a day or so.

I did double check that the filter was not binding on anything as that also has been raised a couple of mm but it is still fine. That does raise the question though that the top of the filter is NOT actually sitting against anything so any bits that the filter is supposed to catch can just go over the top edge anyway! Even more so before my mod!

The only thing I was not sure about was the fact that raising the jet does actually lessen the maximum number of turns available on the shaft. From memory (I forgot to check) in OEM form the shaft has about 2 1/2 turns available. After my mod it now has just a tad less than 1 1/2 turns available - luckily that seems fine as I checked previously and it only needs 1 1/4 turns to get the full flow from the Mara X so I should be fine 🤞


----------



## woodbar

DavecUK said:


> The Lelit ones are EDPM with an ID of 6.07 and a diameter(thickness) of 1.78
> 
> The quoited ones of 10 mm is enough difference to catch on entering the bore and possibly cause problems...have you measured and double checked the sizes?


 Yes, that is exactly what I measured the OEM one at and what I actually ordered - in Viton and EPDM.

That quote from the manufacturer was for OD and not ID so the ones I am using are ever so slightly smaller in OD than suggested.

I have now fitted my last remaining OEM green ring, after my mod, so there can be no doubt about the size or authenticity of what is fitted.

I think you might be "speed reading"?

Lelit and the ones in my kit as well as the spares I ordered:-

6.07 ID + 1.78 CS + 1.78 CS = 9.63 OD

The ones that the manufacturer quoted :-

6 ID + 2 CS + 2 CS = 10 OD - so slightly bigger but I have not used these.


----------



## woodbar

If I have no success with this mod I will probably just do away with the lower O ring which in standard form does not actually seal anything for a considerable range of valve adjustment - with the valve fully shut off and therefore maximum OPV pressure inside the FCD it is totally exposed in the water - so you are only relying on the top O ring for water tightness in any case!

The only thing it does do is probably centralises the spindle to make sure the needle lines up with the hole in the jet as you start to close the valve - the rest of the time it's in "chocolate fireguard" territory!

To be continued.....................


----------



## woodbar

Well, partial success.

Had another strip down today and the lower O ring is still intact - just! Looks a little stressed though.

So my modification of raising the jet so the needle valve shaft does not screw down so low seems to have had some success although I note I can no longer reduce the flow to zero - presumably my cobbled together spacer is allowing some slight bypass around the jet - it still allows all the adjustment I need though.

I was intending to remove my extra spacer and the lower O ring for the next "testing" phase but I have left it all alone for the moment - see how long it keeps working for!


----------



## woodbar

I've been very lazy recently - only just got around to doing a backflush with Pulycaf and took the opportunity to check the dreaded O rings on the flow control. Was surprised at how little gunge came out after nearly three months use - although I do a water backflush every day.

I noticed I had a couple of green strands of rubber in the filter and one which came out stuck to the outside of the mushroom? Thought this might be from the large O ring at the base of the mushroom but had a close look and it looked perfect.

Presumably this residue was from the upper top O ring as that is the only other OEM green one left in there. Replaced both the top ones with the EPDM versions which seem to last about a month - @ 4 coffees a day!

When I took out the cam lever arm to grease the mechanism I was a little disappointed to find that there was absolutely no grease residue on the cams or lifters nor on the little inner locating spigot - there was a huge amount of congealed "chalky" looking grease between the cam and the outer housing (that the brass shaft runs in)! This is the first time this has been dismantled so it would seem that during factory assembly someone just put one huge dollop of grease on the outermost side of the cam and screwed it all together?

Anyway, it all got a good clean, dry and a suitable application of Molykote. Try as I might I could not get the cam back in place and had to remove the lower pre-infusion / dump valve assembly (which I wanted to check anyway) and the cam went back no problem then!

All in it took me a couple of hours to sort out - going slow as I wanted to make sure I got it right and learn how it all worked - I also cleaned and descaled the little Krups Nespresso (consider my mouth washed out!) machine concurrently - which was looking a bit forlorn as it is only for SWMBO and even she has not used it for a month or so!


----------



## woodbar

It seems everyone else's flow control is now working perfectly?🤔

Anyway, just an update - I have now obtained and tried the Coffee Sensor FCD Version 2 device on my machine.

The top housing is now in two parts (very similar to the Lelit version) which means that:

1) The 2 spindle O rings are now always located within the bore in the top housing throughout the total range of adjustment! This will hopefully increase the reliability of the lower O ring exponentially.

2) To check, clean or grease the device you now only have to remove the top fitting - the lower assembly (mushroom & jet etc) stays in the group. This means you no longer have to remove the complete assembly and dismantle the mushroom from the top housing to get at the O rings.

I have been using this for a week or so with good results so far and the shaft is considerably smoother to adjust than previously.

With my OPV set at just a tad over 9 bar I get the standard 5.1 ml flow at 1.5 turns opening - same as on the old version.

I have never fitted the stronger lower spring as I prefer the slow preset pre-infusion as, apart from anything else, it gives you a bit of extra time to judge how the shot is progressing at the start and decide if the flow needs tweaking if your tamp or grind has wandered a bit!


----------



## woodbar

Just an update on the Coffee Sensor FCD device V2.
Checked, cleaned and greased the valve and O rings to day - did not really need it as all were in perfect order anyway - that's a relief!


----------

