# Mara X - maybe a small blockage?



## Glen (Feb 16, 2021)

Since installing the Coffee-Sensor flow control kit I've noticed some irregularities with the amount of water being purged when I drop the lever to stop the shot.

Usually nothing comes out after pulling a shot, whereas before the flow control kit was installed there was always water purged. Also once I noticed it was very hard to fully turn the flow control knob around to the fully open position, but after closing again it went back to normal.

Also even when doing a back flush with the blank filter there has been no water purged until about the 2nd or 3rd flush, and then only a little.

This morning's backflush purged the normal large amount of water which surprised me. After examining the water which I caught in a small plastic container, I saw a small piece of contamination which I remember seeing fall into the boiler when I changed the Temp Probes a few months back when I was having the over pressurising fault during heat up.

The original probes are sealed with a compound which breaks up and can fall inside the hole when you remove the probe.

The other strange thing this morning was that after it's full 60 mins of warm up time since it automatically came on by the smart switch, I noticed the warm up light start to flash again for a couple mins, and my stick-on thermometer on the E61 showed it was still on around 80 when it should be up over 90 (I have the switch set to II position as I'm doing light roast at the moment).

Could a small blockage from contamination in the water cause these kinds of issues? What action should I take? TIA guys


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## DavecUK (Aug 6, 2013)

@Glen Contamination with the flow control installed or the standard group would be no different. However, you should check the flow rates with the lever not further open then the open position *you use* when pulling a shot. Measure it. The ability of the E61 group to vent is dictated by the pressure/water in the group when the lever is lowered. If you restrict the flow, or lower it towards the end of the shot...then there won't be much water or pressure to vent!

One of the thing you should always do is split those flow controls, and check the amount of lube on the O rings, often I don't think there is enough. If you don't split it now...it might be VERY hard to do later. Could be the reason for stiffness.

Although this is a different kit...the principle of operation and lubrication is the same...and something you want to be doing every 3-6 months.

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


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## Dave135 (May 3, 2021)

@Glen I have installed the Coffee Sensor Flow Control kit on my Mara X and did experience a problem with erratic flow a few weeks later. I took the kit off and split it just as @DavecUK advised and yep, one of the o rings had broken down and released bits of crud into the system. I'll post a more thorough article with photos into in the flow control thread but wanted to share my experience with you here. I replaced the o rings with the spares and lubed them thoroughly and I've had no issues since.


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## Glen (Feb 16, 2021)

Thanks for that both @DavecUK and @Dave135

So would you say small pieces of crud about the size of this pictured are not big enough to cause any issues?

This morning the pressure gauge or manometer that came with the Coffee-Sensor kit stopped working when I did my back flush. I removed it and checked it for a blockage but there was nothing there. Re installed it, checked it and it worked.

I'll upload a little video of how it works soon.


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## DavecUK (Aug 6, 2013)

They are big enough to cause a problem.


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## Dave135 (May 3, 2021)

Yep, that will cause erratic flow and pressure readings. Did on mine anyway. Looks like a bit of one of the green o rings. This is what I found when I split the flow control.


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## Glen (Feb 16, 2021)

Dave135 said:


> Yep, that will cause erratic flow and pressure readings. Did on mine anyway. Looks like a bit of one of the green o rings. This is what I found when I split the flow control.
> 
> View attachment 58532
> 
> ...


 Wow that looks terrible!

I just uploaded my little checks I did. My gauge started working again but I caught on camera my flow not working properly and then starting to work again.






the fragments I've pictured previously are the same size and colour as the sealant which I saw fall inside the boiler when I changed the temp probes a few months ago.

I guess maybe I need to dismantle everything and try make sure there's nothing blocking anything?

Thanks guys.


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## DavecUK (Aug 6, 2013)

People must split those flow controls and lube the o rings with Molykote 111, or a PTFE ehansed h1 lube before installing. Lube them every 3 to 6 months after that.

I have said this so many times.


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## DavecUK (Aug 6, 2013)

@Glen Was it the brew boiler temp probe you changed?

P.S. You can get that Gauge straight if you use PTFE tape and stop when it's level, just before it's fully tight.


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## Doram (Oct 12, 2012)

Glen said:


> I just uploaded my little checks I did. My gauge started working again but I caught on camera my flow not working properly and then starting to work again.


 A couple of comment after watching your video @Glen - 1) My Coffee Sensor pressure gauge doesn't vibrate and make a noise like yours. Was it like that from the start, or did it start after the gauge came back to life after the problem? As per @DavecUK's comment and the instructions, you need some PTFE tape on the thread and then the gauge sits straight. Do you have the white gasket in there? I couldn't see for sure.

2) I think you are maybe opening the flow control valve too much, and this could potentially cause a problem. On mine, I found the best results with a max movement of about 3/4 of a full turn, and this is enough to get all the flow range that I want (will explain in more detail below). At one point I thought I will be clever (and lazy) and opened the valve a bit too much in order to get some lube on the thread from the outside (just below the flow control lever), instead of doing it properly and putting the lube inside. This was a mistake. I felt a little resistance so stopped, but I think I could go further and potentially this would damage the O-ring as seen in @Dave135's photo. If you have opened too much and damaged the O-ring, maybe this could explain your erratic flow (and potentially the issue with the gauge?).

This is how I use mine: Let's say that completely closed position of the lever is 12 O'clock (the lever stops there without putting any pressure to close further). For the lowest flow, I never go as far as 12 to close the tap, because I don't need to. The Flow only starts at ~10 O'clock, so even for pre-infusion I don't need to go further than 10, usually 9 or 8 O'clock is enough.

Moving to the most open flow position - a 360 degree turn from completely closed (so 12 O'clock again) is the max that I open the tap. At this point I get almost the full flow I got with the stock mushroom. A quarter turn more and the flow already exceeds stock flow, so I never go there.

To sum up, the range I use is usually between 8-9 O'clock for slowest flow, to 12 O'clock (one full turn from completely closed) for maximum flow. So the actual movement of the lever that I use is ~3/4 of a turn, and that gives me all the range I want with no problems so far. I think it's also easier to use and les confusing like that, as if you do less than a full turn you always know where you are by just looking at the position of the lever.


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## Glen (Feb 16, 2021)

DavecUK said:


> @Glen Was it the brew boiler temp probe you changed?
> 
> P.S. You can get that Gauge straight if you use PTFE tape and stop when it's level, just before it's fully tight.


 Hi Dave, thanks for the reply, yes it was the top and bottom temp probes. I put a new replacement on top and moved the one which was on top to the bottom, swapping out the one on the bottom. I had that over-heating warm up fault and after putting the new probe in the top, I turned on the machine and thought that I saw the fault happening again, but in hindsight I'm not sure it was, that's why I put the old probe from top into the bottom spot, thinking maybe it was the bottom probe causing the fault.

Regarding the gauge not being up in the correct position, I had it right before removing it, but when putting it back in it went too far. I put more tape on it again later and got it straight again.

Cheers


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## Glen (Feb 16, 2021)

Doram said:


> A couple of comment after watching your video @Glen - 1) My Coffee Sensor pressure gauge doesn't vibrate and make a noise like yours. Was it like that from the start, or did it start after the gauge came back to life after the problem? As per @DavecUK's comment and the instructions, you need some PTFE tape on the thread and then the gauge sits straight. Do you have the white gasket in there? I couldn't see for sure.
> 
> 2) I think you are maybe opening the flow control valve too much, and this could potentially cause a problem. On mine, I found the best results with a max movement of about 3/4 of a full turn, and this is enough to get all the flow range that I want (will explain in more detail below). At one point I thought I will be clever (and lazy) and opened the valve a bit too much in order to get some lube on the thread from the outside (just below the flow control lever), instead of doing it properly and putting the lube inside. This was a mistake. I felt a little resistance so stopped, but I think I could go further and potentially this would damage the O-ring as seen in @Dave135's photo. If you have opened too much and damaged the O-ring, maybe this could explain your erratic flow (and potentially the issue with the gauge?).
> 
> ...


 Thanks for all the details mate, that's very helpful.

So, one thing at a time, good to know the Coffee Sensor gauges don't vibrate normally, I've now sent a message to the seller to see what they say, I ordered it directly from them in EU so the shipping cost of a replacement won't be nice...

Just yellow PTFE tape on it which I added more to later to get the gauge straight, as it was before I removed it.

About opening the tap too far, well I didn't learn from anyone before hand anything which warned against opening it beyond the equal full flow rate of what the Mara put out before the installation, so I measured the flow rate before, approx 106 grams in 20 seconds, and then kept testing until I found that 1 and a half turns from closed gave me just over 105g of water in 20 secs.

So that's what I was working with. I never opened it beyond that until as I filmed in the video, I noticed that at the fully open position (1.5 turns from closed) i wasn't getting flow, so I opened it up more and that's when the flow started again.

I'm feeling strongly that I have a damaged o ring in there, which came about during normal operation, never having opened it beyond 1.5 turns.

It's annoying because the correct lube isn't easy to come by. I'll have to wait for shipping too. In the meantime I've been using my Mara without the flow control and with the no-preinfusion spring. The coffee hasn't been bad at all.

The other thing I've decided is that the lack of water purging from the bottom when I drop the lever must be from the strong spring not letting that chamber fill during pre infusion. Would that be correct @DavecUK?


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## DavecUK (Aug 6, 2013)

@Glen disabling preinfusion with a stronger spring will reduce the amount of water from the vent tube.

Hopefully people with new flow control devices will split and lube them before installing.


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## cuprajake (Mar 30, 2020)

@DavecUKdoes that count for new machines that come with one pre installed like the bianca?


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## MediumRoastSteam (Jul 7, 2015)

@Cuprajake - pretty certain that the Bianca has E61 pre-infusion chamber effectively disabled by default. But Dave can confirm.

Edit: Here it is:

https://www.coffeeforums.co.uk/topic/55737-why-doesnt-the-bianca-e61-group-have-a-drain-valve/?do=embed


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## cuprajake (Mar 30, 2020)

sorry bud, ment greasing the paddle


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## MediumRoastSteam (Jul 7, 2015)

Cuprajake said:


> sorry bud, ment greasing the paddle


 🙂 - No worries. That one I leave up to @DavecUK to answer. Although I remember him saying something recent that on the Bianca it's a much simpler task than others... Let me see if I find that post.

Edit: Found it! 🙂

https://www.coffeeforums.co.uk/topic/50697-e61-flow-paddle-control-on-vesuvius/?do=embed&comment=850178&embedComment=850178&embedDo=findComment


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## DavecUK (Aug 6, 2013)

Cuprajake said:


> @DavecUKdoes that count for new machines that come with one pre installed like the bianca?


 The Bianca has the stronger spring fitted to the preinfusion (so the chamber never opens) and I am pretty sure they omit the vent valve entirely....at least that's what I would do. This way everything keeps cleaner in the vent side of the group.


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## MediumRoastSteam (Jul 7, 2015)

DavecUK said:


> The Bianca has the stronger spring fitted to the preinfusion (so the chamber never opens) and I am pretty sure they omit the vent valve entirely....at least that's what I would do. This way everything keeps cleaner in the vent side of the group.


 Jake meant whether to lubricate the flow control valve 🙂 - I fell for the same trap 🙂 .

He's effectively asking whether the lubrication schedule every 3/6 months of the flow control valve / paddle is also applicable to the Bianca.


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## cuprajake (Mar 30, 2020)

suppose its the one downside to an e61 machine haha


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## DavecUK (Aug 6, 2013)

MediumRoastSteam said:


> Jake meant whether to lubricate the flow control valve 🙂 - I fell for the same trap 🙂 .
> 
> He's effectively asking whether the lubrication schedule every 3/6 months of the flow control valve / paddle is also applicable to the Bianca.


 Ah...yes absolutely, Lubricate it before using it and then depending on on-time/usage, relube every 3-6 months. it's not a hard job as only 1 nut and the paddle has to be removed... Molykote is good as it hangs around nicely, but I have some Ambersil H1 grease that's also PTFE fortified and good to high temps...I use it on my roaster bearing and will probably use it on the valves...when I remember.

The great thing about E61 maintenance, is it makes the group last for a decade or more before any thoughts of valve replacement etc.. If you can get those little valve Viton pads used inside on the group valves and unscrew the cam followers without them snapping...then it's really cheap to renew....pennies.


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## Glen (Feb 16, 2021)

I finally got some lube and split open my flow control kit which I had sitting in a draw for over a month while I got around to it, and inspected the little green o rings, one was a bit chewed up, so I replaced that one. Wiped some lube around them and put it back together. It's been working good since. 
But the vibrating needle on the manometer hasn't changed. I asked the guy at Coffee Sensor about it and he wasn't helpful at all. Suggested that I had an air lock behind the gauge or something and that turning the tap back and forth might fix it. Does he honestly think I haven't turned the tap yet?


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