# ACS Minima tripping RCD



## poolfan (May 9, 2014)

Hi,

Today I adjusted down the OPV as was a little of 9barg. Once completed, I then began a clean cycle with the blank portafilter in. Each time I switched OFF the pump, the RCD would trip. I eliminated timer plug in case that was fault, however confirmed it was definitely the coffee machine.

Now trying to understand what is now causing the RCD trip - could it be as simply as some water fell in when I had top cover off causing a problem, even though I don't recall any water ingress, but maybe a few drops as I moved OPV tubing from reservoir to sink? As part of the OPV vave adjustment, I followed @DaveC instructional video, and switched off the heater via the PID controller, switching it back on after adjustment completed.

As with an electrical fault on a SS machone, I'm concerned as to what the issue may be. Any advice?


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## jscott (Jun 25, 2019)

Hi, I had a similar problem - see this thread:

https://www.coffeeforums.co.uk/topic/47001-acs-minima-trips-circuit-breaker/?do=embed&comment=679859&embedComment=679859&embedDo=findComment

Sounds like it could be something to do with the solenoid valve on the group? Mine had a trapped wire but it was like that since manufacture...

Probably a long shot in your case but maybe double check you didn't nip a wire when putting the top cover back on?


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## poolfan (May 9, 2014)

So took another look and found an issue, however not the source. Esse tially with a blind portafilter on I ran pump for ~10s and then stopped. After a few seconds I can then see a water leak coming from the underside of the machine. The water on one that seems under steam boiler is dirty water, however likely this is because the underside frame of machine is dirty from manufacture which I noted when I had the back cover off earlier.











Any ideas of source of water leak?

Is there a way I can put the machine to one side and then remove the base to look 'under the bonnet'?


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## Nikko (Aug 20, 2014)

The Minima boilers come with unnecessary holes which are plugged but can leak. That is your starting point.


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## MediumRoastSteam (Jul 7, 2015)

@poolfan, is this a production or beta machine? Ps: you have pinged the wrong Dave. The "right one" is@DavecUK.


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## poolfan (May 9, 2014)

it's production machine


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## DavecUK (Aug 6, 2013)

If I remember rightly it's a production machine purchased from BB last May 2019. Once I stopped being motion sick from the Videos (hope you didn't pay too much for the phone)....I think the water is probably coming from a pipe leading to the brew boiler but it's pure guesswork, certainly don't think it's coming from the steam boiler.

Simple answer, shine a torch in the top have a good look to identify the leak, look around brew boiler area and pipes leading too it. You could also take the case off soe you can get a proper look. If it doesn't look a simple fix, you have 2 years warranty support from BB, let them deal with it.

You might think why should I take the case off...and really it's just less risk than shipping if the fault is really simple...which it might be.


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## poolfan (May 9, 2014)

DavecUK said:


> If I remember rightly it's a production machine purchased from BB last May 2019. Once I stopped being motion sick from the Videos (hope you didn't pay too much for the phone)....I think the water is probably coming from a pipe leading to the brew boiler but it's pure guesswork, certainly don't think it's coming from the steam boiler.
> 
> Simple answer, shine a torch in the top have a good look to identify the leak, look around brew boiler area and pipes leading too it. You could also take the case off soe you can get a proper look. If it doesn't look a simple fix, you have 2 years warranty support from BB, let them deal with it.
> 
> You might think why should I take the case off...and really it's just less risk than shipping if the fault is really simple...which it might be.


 Thanks Dave, is there an easy way to inspect as I had the back/side cover off already and saw nothing at all - a way to get a look in from below as that would be ideal, I'm guessing these machines not meant to be laid on a side right?

I'll take another look in daylight tomorrow to see if I can find the source, else take your advice and pack it up...


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## Rob1 (Apr 9, 2015)

@poolfanDo the production machines have a plate you can remove under the group to get to the solenoid? I'd imagine they do...remove that and have a look inside. I had an issue where the dispersion screen bolted to the solenoid would fall off and get trapped underneath, the result would be water splashing up and into the machine. On mine it landed on the wires going to the pump and made it run even when I switched it off. It happened again recently and was accompanied by a burning smell which was coming from one of the (wet) solenoid cables in contact with the group syphon.

Easy fix in the end was to turn the machine off, dry everything out and use a wrench to fix the solenoid dispersion thingy into place rather than finger tightening. Problem hasn't recurred since.

It was most obvious when backflushing with a blind filter as that meant a much larger volume of water going through the solenoid than usual. From your description you should check the solenoid first as the fault will be immediately apparent. If not that you'll be looking for small leaks in piping.


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## DavecUK (Aug 6, 2013)

Best not to lay it on it's side, you should be able to track with a torch. Robs suggestion is a good one as water leaking in main case is unlikely to trip RCD.


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## poolfan (May 9, 2014)

Went at it this morning and found the threaded shroud / cover under the solenoid had dropped off, caught at base of solenoid cover, only obvious when I removed it. so presumably water spraying out when discharge opens, shorting solenoid connections, dripping down through inside. 
Was just about to post and then read your reply Rob which describes the very same thing, so thanks for reply, feeling much better that this is the source of problem
I'm gonna put it all back together now as seems all dry inside from overnight, try again!!

thanks for the help guys, much appreciated!!


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## DavecUK (Aug 6, 2013)

I had a suspicion Robs was on the money with that one because as I said there is not really anything underneath that can short out because of a leak...the solenoid valve connections...yes. It was also clearly near the front. Glad it's sorted and saved a risky trip. Don't tighten the vent discharge "perlator" too much because that entire solenoid fits like a bayonet lightbulb for super easy replacement. Just pull off spades untwist like a light bulb , regrease o ring and refit.

Ignore anything written by Nikko on the Minima, he basically trolls about it and pretty much anything I review, it's unlikely he will have much to say of help to you. Listen to people like @Rob1 who *actually* has a Beta Minima, so likely has had more issues he has solved than any production machine. It produces a great shot, steams fantastically well and the components inside are robust.


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## poolfan (May 9, 2014)

thanks again guys. Was sounding pretty grim stuck at home with no coffee!!


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## DavecUK (Aug 6, 2013)

poolfan said:


> thanks again guys. Was sounding pretty grim stuck at home with no coffee!!


 It's why I keep a few spare machines hanging around


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## Jony (Sep 8, 2017)

DavecUK said:


> It's why I keep a few spare machines hanging around


 Posh xxxx must be horrible to have 5 machines?


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## DavecUK (Aug 6, 2013)

Jony said:


> Posh xxxx must be horrible to have 5 machines?


 No I've only got 4 hot and running at the moment, the other 5 are not on the counter 

Of the 2 BTC machines, which don't count, one of them is being used by Mum in the Annex...she likes it.

P.S. I keep more than one hot and running so it's like a UPS but for coffee...instant fallback capability. "hot standby", if you like, with multiple redundancy across more than 1 location (and site, counting the annex) As far as grinders go it's "warm standby."


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## Vollbart (Jan 27, 2019)

I've been having this exact problem.

When backflushing, after the system vented, the pump turned on again and the timer restarted. After perhaps a second or so the pump/timer then went off again on its own, before alternating between being on and off at a rapid rate. I then manually turned the machine off and it returned to normal when it was turned on again a few minutes later. Looking under the machine I could see a puddle.

I've just taken the cover below the group off and low and behold the threaded shroud thing was just loose floating around at the bottom of the cover, probably exacerbating the problem as the water must have been hitting it and spraying back up into the machine.

Any idea if this been acknowledged by Paolo/ACS as some sort of flaw when assembling? Or will this work loose again? Happy that I've been able to sort the problem out myself but want to feed it back if it's not been addressed. Timewise it's likely mine was from the same batch as poolfan's so hopefully it's been sorted.


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## Rob1 (Apr 9, 2015)

Vollbart said:


> I've been having this exact problem.
> 
> When backflushing, after the system vented, the pump turned on again and the timer restarted. After perhaps a second or so the pump/timer then went off again on its own, before alternating between being on and off at a rapid rate. I then manually turned the machine off and it returned to normal when it was turned on again a few minutes later. Looking under the machine I could see a puddle.
> 
> ...


 You just need to tighten it a little. Not too tight just nip it up a touch with a wrench. Mine hasn't worked loose since I did that.


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## Vollbart (Jan 27, 2019)

Yep all done, just leaving it to dry out. Thanks all for sharing your experiences and advice.


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