ASHP tripping electric....HELP!!!

[Chriswills]

My 12 year old ASHP has worked fine up until now where it has this morning tripped the electric. Despite countless times of switching it back, it goes off again.

Its our only source of heat.......any ideas please.

[dpmiller]

How handy are you with a multimeter? Unplugging (say) the fans and the compressor and re-trying could be a start but lookiing at that trip, I might start there.

[ProDave]

That is the RCD it has tripped, so an earth leakage fault not an over current fault.

 

You really need an insulation tester to find that, not a multi meter, and pray it is not the compressor that is the faulty item.

[Nick1c]

We had something similar after a storm, it turned out that it was due to damp getting into an outside socket on the same circuit. No idea how it was checked /  sorted out. 

[TonyT]

Time to call in an electrician 

[Chriswills]

I have a sparky coming over now just to check the RCD over. If that all checks out where do I go from there?

[ProDave]

  On 30/11/2021 at 17:34, Chriswills said:

I have a sparky coming over now just to check the RCD over. If that all checks out where do I go from there?

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The sparky needs the check everything, bit by bit. 

 

Start with the isolator switch and supply cable, i.e. with the supply disconnected inside the ASHP does that IR test okay?  It could be water in the isolator switch for instance.

 

Then he needs to check individual components inside the ASHP like valves, pumps, fans, compressor, sensors etc.  Test each by disconnecting them from the control boar and IR test to earth.

 

Check everything inside like control boards for any sign of them being wet in any way.

 

Right now is not the best time, a lot easier in daylight.

[tonyshouse]

I think overcurrent problem on startup 

[Chriswills]

Thanks guys. Seems to be all sorted. He replaced the breaker and now it’s working Ok. For now at least

[ProDave]

  On 30/11/2021 at 19:50, Chriswills said:

Thanks guys. Seems to be all sorted. He replaced the breaker and now it’s working Ok. For now at least

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Thanks.

 

I hadn't realised until I looked again that MCB and RCD are outside, forming the job of an isolator as well. It is highly likely water has got in somehow.

 

Lets hope that was all it was.

[dpmiller]

I've seen those Wylex RCDs do odd things before.

[SteamyTea]

@Chriswills

So as you have had this ASHP 12 years, you had any other issues with it?

[Chriswills]

  On 01/12/2021 at 10:01, SteamyTea said:

@Chriswills

So as you have had this ASHP 12 years, you had any other issues with it?

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No issues with the pump at all until now

[Chriswills]

Still having problems and we thought it was all fixed. 
Still tripping at the outside wall. Sparky came around and confirmed it was the ASHP unit at fault. 
he tried disconnecting items to see if he could pin point the issue but to no avail. 
I need some help here guys please. 
He even removed the earth from the RCD, it ran a little longer but then tripped out through the neutral he said. 

Edited December 20, 2021 by Chriswills

[ProDave]

Start by unplugging everything inside that you can, fans, compressors, valves, sensors etc.  MAKING SURE you note what went where so it can all go back in the right place.  It won't run and it will throw some errors, but if it does not trip you are making progress.  Then put the unplugged items back one at a time until it trips and you have your likely fault.

 

You might need a better electrician?

[tonyshouse]

The inrush current on heat pumps can be very high. Different breakers are available that can cope with that 

[Chriswills]

Just an update, I have been switching off and removing bits this morning to isolate the issue. It seems if I remove one of the compressor enabaling relays it works fine, heats up and does not trip. I thought eureka that it was a faulty relay, so put the KA6/1 into KA6/2 and it trips immediately. So I think its compressor related.

If I leave out the relay and run it, it works fine, is this advisable in the short term as the house is rather cold now?

[Chriswills]

Image shown with relay removed

[dpmiller]

Is there a soft-start device? Have you any way of testing the capacitors? (top right of first piccy)

 

Try seeing where that orange wire on the relay socket goes to..

[Chriswills]

  On 21/12/2021 at 10:34, dpmiller said:

Is there a soft-start device? Have you any way of testing the capacitors? (top right of first piccy)

 

Try seeing where that orange wire on the relay socket goes to..

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Do you mean the C1 Capacitor?

Can’t see where the wire goes too

[ProDave]

If it "works fine" with a relay removed, something must be not working so is it really "working fine" or is it detecting a fault (e.g. no compressor) ans using a backup e.g. electric resistance heating element?

 

does it show any error with this relay removed?  Can you tell what is not operating, e.g. no compressor noise or no fans running?

[Temp]

Worn out compressor can cause it according to all the online guides.

[Chriswills]

  On 21/12/2021 at 12:36, ProDave said:

If it "works fine" with a relay removed, something must be not working so is it really "working fine" or is it detecting a fault (e.g. no compressor) ans using a backup e.g. electric resistance heating element?

 

does it show any error with this relay removed?  Can you tell what is not operating, e.g. no compressor noise or no fans running?

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No error with relay removed unit heats up ok. Is it safe to run with relay out?

[dpmiller]

As Dave says it could be heating on a resistance heater so you'll need to check carefully for clunks and hums from the compressor

[Carrerahill]

  On 20/12/2021 at 20:17, tonyshouse said:

The inrush current on heat pumps can be very high. Different breakers are available that can cope with that 

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It worked fine for 12 years so unless a motor has seized or about to die, which I don't think it has/is, then I cannot see the current suddenly increasing above the rating of the 12 year old MCB. If a higher current breaker was the fix then I would be more concerned about what was actually wrong further down the line and could the associated cabling then handle the increased current. 

 

As the OP said it ran longer with the earth pulled off the RCD this indicates leakage due to a failing components or moisture ingress. This fault, therefore, does not appear to the current related. Current and earth leakage are two different things.