# Minima - slight pump stutter, maybe 'fishy' smell



## ryan111 (Jul 24, 2018)

Hi All

I am going to take apart the machine and have a look around tonight, however I thought I would ask if anyone has any ideas. My Minima is one of the Beta version, nearly 3 years old and is on ~ 10 hours a day. Cleaned regularly, descaled ever 6 months or so.

I have recently noticed a very occasional stutter from the pump, less than 1/2 sec, maybe 3-4 times within 5 seconds, it comes with a corresponding blip (drop) in pressure but then the shot always completes. I also think there is a slight fishy smell coming from the internals (like you get when wiring/insulation is heating).

Before I take it apart to inspect, does anyone have any experience or thoughts on where I should be concentrating.

Thanks,

Ryan


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## DavecUK (Aug 6, 2013)

@ryan111 Open it and check for any loose connectors...it might be what's causing the pump to stutter. When a connector is loose to even a relatively low power device like a pump that consumes 50W, a huge amount of power can be drawn if it arcs, along with excess heat....and the smell as the polymer of the connector degrades.

Also remove the solenoid cover shroud and check the wires there are tight.

Take some photos...


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## Rob1 (Apr 9, 2015)

I always says this about the Minima....but I had the same problem with the pump randomly stopping/starting and then it just refused to turn off one day along with an electrical/burning smell. It was the wires on the solenoid touching the thermosyphon and maybe some water splashing up into the machine from the shower head thing on the solenoid valve falling off which got onto the pump. I can't remember which was causing the issue but I dried everything off and turned the solenoid valve a little so the wires weren't touching the thermosyphon return and I haven't had a problem since. I can't tighten the shroud completely against the case though as it forces the solenoid to turn...


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## ryan111 (Jul 24, 2018)

Thanks for the info.

The fishy smell turned out to be nothing to do with the machine. It is my water (Copenhagen - very hard) and the Peak water filter. Its a known thing and very prevalent in Copenhagen.

I took the machine apart and didn't find any loose connections or obvious electrical issues that would cause the pump noise. For the pump, have taken a video if anyone has any thoughts on it (will upload later). I am leaning towards getting a new one and replacing it as they sound cheap to see if it resolves.

However I did see a couple of other things (see attached photos). I know there is more calc around even after the jug filter than I would like but I thought the regular descales would do a decent job controlling it.

photos are, bottom of steam boiler, top of steam boiler, connector in box


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## MediumRoastSteam (Jul 7, 2015)

I won't comment on the electrical connectors, as I don't know what causes the browning.

you should really think about the water you feed your machine with. Consider getting a Osmio Zero, or distil the water and remineralise it, or something like that. The water here in SE England is as hard as nails, and, the advice is to control what goes in.

I, as an example, distil the water and remineralise. Not ideal, but as you found out yourself, the Brita Or Peak doesn't do a lot to remove limescale, mainly as they won't last as long as advertised with such conditions.

personally, I'd descale your machine - who know what it looks like inside 5e boilers and around the pipe work.

and then&#8230; try preventing it rather than remediate.

Re: fishy smell&#8230;

https://www.coffeeforums.co.uk/topic/40693-peak-water-from-mcd/?do=embed&comment=750389&embedComment=750389&embedDo=findComment

https://zerowater.co.uk/apps/help-center#why-does-my-filtered-water-taste-acidic-or-fishy


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## Rob1 (Apr 9, 2015)

I think the Beta Minimas were made with bolts and washers or something rather than thread seal and a lot people reported leaks. It looks like that's happened here and scale has formed sealing them up. Service boilers will need very regular flushing to prevent scale build up. I'm guessing you've been steaming milk without regularly emptying the boiler completely via the hot water tap and refilling with fresh water?

Do you think some resin beads may have got into the pump?


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## DavecUK (Aug 6, 2013)

Temove and check threads for corrosion, in the betas they didn't use thread sealant, which allowed the brass threads of the plugs to bathe in a water environment with the steel. The minerals in the hard water actually promote corrosion in this instance and your waters really hard, so there would have been plenty of galvanic action...Check the threads are not rotted in the brass bolts. If they are OK wrap em with PTFE tape to stop the corrosion and even use a touch of Molycote....then refit. The use of thread sealant instead of a washer, would have stopped water hanging about in there and the corrosion, they learnt this after the betas....as it wasn't thought the corrosion would be an issue especially with the coating on the brass.

If the thread has gone, you can fit taper stainless plumbing fittings, wrap with PTFE, but be really careful, don't do them too tight. I can't find the instructions I gave someone because the search on my support forum isn't working for some reason....but you will figure it out.









Check connector on Gicar is not loose...otherwise, that should sort it out...I'd also stop using that Peak and move to an RO solution, like the Zero!


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## DavecUK (Aug 6, 2013)

I instructed @mctrials23 on how to fix his machine by private message. I do remember these were the bolts I advised him to get

https://www.bes.co.uk/screwed-hexagon-blanking-plug-stainless-steel-1-4-14484/#product-details-tab

Unfortunately I didn't post the fix on the forum, due to a certain amount of noise being created making it impossible to help him publicly at the time, and I was not a moderator to put a stop to it.

use lots of PTFE *and only nip them up cos they are tapered threads going into a non tapered fitting* and unlike the normal use of PTFE to allow a tapered thread to be tightened up properly....you will be using the PTFE to seal!! They will work and they will completely fix the problem. Obviously the little steel bolt at the bottom is not the same fitting and you could try not removing it, see if it leaks, or remove, clean and check it...I doubt it will be corroded.


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## ryan111 (Jul 24, 2018)

Rob1 said:


> I think the Beta Minimas were made with bolts and washers or something rather than thread seal and a lot people reported leaks. It looks like that's happened here and scale has formed sealing them up. Service boilers will need very regular flushing to prevent scale build up. I'm guessing you've been steaming milk without regularly emptying the boiler completely via the hot water tap and refilling with fresh water?
> 
> Do you think some resin beads may have got into the pump?


 I do flush the boiler to empty about every two weeks. I don't think could resin beads could get through, there is a filter on the end of the pickup.


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## ryan111 (Jul 24, 2018)

DavecUK said:


> Temove and check threads for corrosion, in the betas they didn't use thread sealant, which allowed the brass threads of the plugs to bathe in a water environment with the steel. The minerals in the hard water actually promote corrosion in this instance and your waters really hard, so there would have been plenty of galvanic action...Check the threads are not rotted in the brass bolts. If they are OK wrap em with PTFE tape to stop the corrosion and even use a touch of Molycote....then refit. The use of thread sealant instead of a washer, would have stopped water hanging about in there and the corrosion, they learnt this after the betas....as it wasn't thought the corrosion would be an issue especially with the coating on the brass.
> 
> If the thread has gone, you can fit taper stainless plumbing fittings, wrap with PTFE, but be really careful, don't do them too tight. I can't find the instructions I gave someone because the search on my support forum isn't working for some reason....but you will figure it out.
> 
> ...


 Thanks David,

I will look at replacing those and add tape.

I put the machine back together and got a day of coffee out of it. Today the pump still runs (or sounds like it does) but the pressure is only coming up to about 2 bars.


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## DavecUK (Aug 6, 2013)

There's a lot of scale on those fittings, there the pump or solenoid or both could be scaled. Does it leak from the vent during the shot. Remove the shroud to check.

Pumps an AR15 if you want same replacement, or fit ulka or Lelit quiet pump.

Definitely sort your water out.


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## Rob1 (Apr 9, 2015)

ryan111 said:


> I do flush the boiler to empty about every two weeks. I don't think could resin beads could get through, there is a filter on the end of the pickup.


 Your water must be really bad then, or you just steam a lot of milk. Actually it wouldn't take too much steaming at all over two weeks for water to go from non scaling to scaling. Whatever the peak is doing might not even be enough for the brew boiler. Get it checked with a GH/KH water test kit for fresh water aquariums (droppers are better than paper).


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## ryan111 (Jul 24, 2018)

Thanks all, the water is famously hard here. I was hoping the Peak plus regular descaling would cover it. I also hope the scale on those bolts is not representative of the scale inside the machine because they miss out on the descaling.

Is there any way to test the pump separately? What pump would you recommend if I am replacing it anyway? Should I just replace the solenoid too?

Thanks


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## DavecUK (Aug 6, 2013)

@ryan111 do your diagnostics first. When you remove the plugs you can look in the boiler.


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## ryan111 (Jul 24, 2018)

I'm getting close to handing it over to a professional to take a look.

I turned it on, put in the blank portafilter and ran it, the pressure on the machine and head gauges both went to about 2 bar, but then after about 15 seconds with the pump running the pressure in the steam boiler went up sharply and released the pressure release valve on it.

When I ran the steam wand there was water in the steam wand (temp was at 125), so I think the tank had overfilled.


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## DavecUK (Aug 6, 2013)

ryan111 said:


> I'm getting close to handing it over to a professional to take a look.
> 
> I turned it on, put in the blank portafilter and ran it, the pressure on the machine and head gauges both went to about 2 bar, but then after about 15 seconds with the pump running the pressure in the steam boiler went up sharply and released the pressure release valve on it.
> 
> When I ran the steam wand there was water in the steam wand (temp was at 125), so I think the tank had overfilled.


 I think as you are finding multiple "fault", some that are faults, some that are not, clearly hard water and probably scale inside the machine. Without doing a step by step proper diagnostics procedure, you could end up chasing your tail. I've tried to help by suggesting next steps...which were not just connect it up and see what happens. You needed to do a staged methodical approach, this is what a professional would do, so perhaps best to give it to them.

The first step should have been to remove those plugs, inspect them and inspect the boiler inside for scale.....

When you get your machine back, you absolutely must sort the water situation out...I suggest RO.


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## ryan111 (Jul 24, 2018)

DavecUK said:


> I think as you are finding multiple "fault", some that are faults, some that are not, clearly hard water and probably scale inside the machine. Without doing a step by step proper diagnostics procedure, you could end up chasing your tail. I've tried to help by suggesting next steps...which were not just connect it up and see what happens. You needed to do a staged methodical approach, this is what a professional would do, so perhaps best to give it to them.
> 
> The first step should have been to remove those plugs, inspect them and inspect the boiler inside for scale.....
> 
> When you get your machine back, you absolutely must sort the water situation out...I suggest RO.


 I appreciate the help, and will go through the steps, just have to wait for the parts and the time to pull it apart again. Thought these might have indicated something else. I won't post again until I have gone through them


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## DavecUK (Aug 6, 2013)

@ryan111 The problem is that the root cause can often result in multiple faults...which you then end up "fixing" the wrong way round. e.g. for a hypothetical machine.



Poor flow rate


low pump pressure


service boiler sometimes over fills


Poor steaming


vacuum breaker leaking


not venting properly


leaking


heating element or something triggering RCD


Temperature reading incorrectly or erratic


You might think just everything is going wrong....cost a lot of money to fix...when the root cause might just be the water/limescale....fix that, descale properly and thoroughly (engineering descale) and bingo all the problems go away, or possibly almost all....you then fix what's left.

I've run a Minima for many years and put a lot of shots through it...not a single problem. I use RO water and cut it with Bicarb sometimes. For all my machines I almost never get problems. When I replaced the brew boiler O ring on my Vesuvius (which is probably 6 years old, the boiler was completely clean inside.


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## ajohn (Sep 23, 2017)

DavecUK said:


> descale properly and thoroughly (engineering descale)


 I need to do one of those on my Sage DB. It was a refurb and had been descaled and again by me when it arrived here. It's an easy machine to descale but there was a problem. A descale can only remove so much scale. The previous owner had managed to build it up to above that level. I know because I descaled twice on the trot once and the PID behaved differently. Scale interferes with the heaters ability to heat. I did another one recently ahead of time and the same thing has happened again. The only way I can find out if the boilers are scale free is to look in them.  I'm ready. I have my 300ml syringe and some tubing to empty the boilers and get any sludge out. Apart from that much depends on what I can see.


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## ryan111 (Jul 24, 2018)

DavecUK said:


> I instructed @mctrials23 on how to fix his machine by private message. I do remember these were the bolts I advised him to get
> 
> https://www.bes.co.uk/screwed-hexagon-blanking-plug-stainless-steel-1-4-14484/#product-details-tab


 Is the 1/4 inch the right size? It seems small but I have the bolts back in the machine so I can't check.

While still a work in progress. I gave it a basic descale before pulling out the bolts to check the condition (they do need replacing) and looked in the tank, looks clean and free of calc. Together it will now come up to pressure, albeit a bit slower than normal and with a stutter still. I have ordered a new pump anyway as I will fit the quiet one you mentioned. Once all the parts arrive I will replace bolts and pump together, give it a full check of everything surrounding the pump and see how it goes.


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## ryan111 (Jul 24, 2018)

For anyone who is following this message.

The bolts above are the right size. I replaced them and it seems to be fine.

I replaced the pump with one of the 'silent' ones. It is quieter, but not a huge difference.

The ramp speed still seems to be slower than it used to be (8ish seconds) but the pump is not stuttering


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## MediumRoastSteam (Jul 7, 2015)

ryan111 said:


> I replaced the pump with one of the 'silent' ones. It is quieter, but not a huge difference.


 Which pump did you replace it with?


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