alpha HE 33 boiler tripping RCD when windy

[hardbasta]

hi, picked a job up today from a landlord saying gas fitter been out and blamed faulty electrics for RCD tripping so went out to investigate. Apparently this has been going on for 4 years since it was installed. story so far.

1. boiler fitted 2008, trips RCD in cellar out roughly once a week.
2. installer comes back out and says boiler is fine, electrics are at fault.
3. Electrician comes out (not me) and says wiring & RCD are fine, boiler is at fault.
4. installer comes out again and gets in touch with Alpha, who advise him to alter the flue.
5. boiler runs much better, occasionally tripping RCD. gas installer blames electrics again.

At this time, I will point out that the lady is 96 and lives alone so has to ring for someone to re-set the RCD every time it trips.

6. electrician comes back and installs an RCD unit next to the boiler, to stop the one in the cellar tripping, and to make sure that nothing else is causing the trip.
7. same problem but now boiler trips new RCD occasionally, usually when windy.
8. gas installer disappears of face of earth, and boiler is long out of guarantee.
9. Last week, new gas fitter went out and serviced boiler and said he could not see a fault or see any signs of water near the electrics.
10. I was called out today and tested the RCD which is working fine, so there must be a problem with the boiler.

I really don't want to go back to landlord and say "its a fault with the boiler" without a possible reason, as this poor lady has spent 4 years being passed back and forth, so would really like to help her sort it.
Please note I am a registered electrician and will not be carrying out any work on the boiler, I would just like to be able to offer advice to a solution to this ongoing problem.

cheers, Royce.

 

[Agile]

I can see no connection with wind unless water is getting into boiler.

Needs an RGI to open and inspect the boiler internally.

Tony

 

[hardbasta]

hi Agile, thanks for the reply, but the RGI has been and inspected the boiler internally, and said there is no problem (point 9). he says there is no internal problem. but i know 100% that the supply up to the boiler is working fine, tested with fluke 1652 calibrated 3 months ago. there must be a problem with the boiler, I would like to know if there is a common fault on these boilers tripping rcd's, or if there is something the RGI has missed.

cheers, Royce

 

[Tibbot]

Other than polarity, has anyone checked for earth continuity/resistances of all internal components?

 

[picasso]

If you have a milliamp clamp meter put it on the cpc and see if the boiler is "leaking", it might be running on 29ma and not taking much to trip the rcd at 30ma.

 

[matt1e]

there must be a problem with the boiler, I would like to know if there is a common fault on these boilers tripping rcd's, or if there is something the RGI has missed.

cheers, Royce

Does the boiler have external controls?
You need to disconnect them and take them out of the equation first before blaming the boiler ( a nail or screw through the room stat cable is a common fault for example)

Matt

 

[past3bar]

No definitive answer ? I was called out to a 33HE tonight with the exact same problem.

 

[Agile]

No definitive answer ? I was called out to a 33HE tonight with the exact same problem.

Well I am sure that is interesting!

But it would surely be more interesting if you said what was the problem in that case.

Because of all the possible causes it may not be the same as the OP's problem.

I cannot see how the OP's engineer can say 100% that the boiler is not at fault if he has not measured the earth leakage. Very few RGI's even know how to do that let alone have a suitable meter.

Tony

 

[Gasguru]

I've been in exactly the same position with one of my customers...it's a tenanted property that I just fo the gas safety for but has a maintenance contract. The boiler is a HE CB33 (AFAIR a near identical boiler).

I think Alphas view is that water ingress via the flue can get onto the flue thermostat located very near the flue connection at the top of the boiler. Now in my case this may have been the issue a few years ago. After 29 visits by a well known boiler maintenance company (not BG this time though) I got called in. The landlord was getting presurised to replace the boiler which was only a couple of years old). I found the problem was a polypropylene elbow on the bath waste above the flue that had begun to disintegrate in the sunlight. Ocassionally water would leak from the joint down the wall into the flue and hit the flue stat terminals tripping the RCD.

Now in the last year the problem has started again. It's definitely not down to water ingress this time though. I have isolated the boiler fan/gas vale and pump. It would trip the RCD as soon as the ignition started.

I have avoided getting too involved this time but AFAIR in the end the boiler was put on its own circuit. I'm not sure whether the circuit was protected with just an MCB or RCBO. I gave up trying to deal with so called electricians sent out by the maintenance contract company.

I can almost guarantee that any gas installer attending will not have either the knowledge or equipment to verify that the boiler components are not causing the RCD to trip.

I suggest you check the leakage on the ring final circuit, and then the boiler components individually ie. the pump, fan and gas valve. You'll need to go with a competent boiler engineer so you can wire up each boiler component and check for leakage. It's a little more tricky to test just the pcb on it's own for leakage but can be done. I found it would only trip the RCD during the ignition process so clearly the spark generator circuit added to the earth leakage.

The favorite boiler component to trip an RCD is the pump...so check the terminal box first for moisture.

 

[ianmcd]

Check the resistance of the fan motor at cold then run the boiler till its hot and check the fans resistance again, it might be faulty when hot ,

 

[twiggy27uk]

I need a few ideas here too. Sorry to dig up an old thread.

Right hecb33 combi boiler from alpha. Installed in 2007/08.
2008 flow switch went and diverter valve gone replaced on homeserve contract
2009 flow switch gone and diverter valve again replaced. Still on contract.
2010 flow switch replaced and leak on diverter valve so replaced again still on homeserve contract.
2011 flow switch breaks down. Replaced on homeserve contract. Diverter valve fine but leak in heat exchanger so replaced.
2012 boiler starts tripping the main fuseboard rcd. Alpha called through homeserve and guy checks and replaces the flow switch due to shorting out. Boiler stops tripping.
2013 the rcd starts tripping again. Engineer replaces flow switch. This trils the rcd still. Then the fluestat trips out the boiler. This is also replaced. Boiler still tripping out so he comes back and replaces the fan unit which after 2 days still kept tripping the rcd.
2014 engineer comes back and after checking fluestat seeing it looked ok he changes the pcb in the boiler. The boiler then seems to settle down. This was january.
During the summer it tripped once which we cant understand.
September and today its tripping again when turning on. Only the rcd on the fuseboard again and if isolated so the boilers off nothing else trips. The boilers on a mcb on 1 side of a split fuseboard with 2 rcd areas. Lights sockers for downstairs on 1 and sockets lights and boiler upstairs on the other.
Boilers had a new wall stat earlier this year which is a 3 wire. Been checked and is fine. Only thing left to change is the pump but never had a problem with that as its starts up and sounds like its driving itself round.
Is there any ideas what it could be?. Would you say the boiler is fit for purpose?. I need to know my consumer rights with regards to getting it finally sorted. I know homeserves contract is crap but how long do i have to have a guy out per year before they mabey see sense and either fix it for good or give in and say its not fit for purpose and replace free of change?

Cheers.

 

[twiggy27uk]

Ok update on my problem.

Had alpha engineer out this morning again. Yesterday boiler was tripping everytime i turned heating or a tap on.
Today boiler fired up perfectly and been running fine with boiler engineer here.
He asked for an alpha technical engineer to join him on 2 seperate requests. They would only speak via phone.
First thing they said was flue leaking water back onto the fluestat which is placed behind the flue drop level. My engineer has already replaced this twice.
Then they said pressure valve which yet again been replaced already.
Then they said fan unit to which the engineer has also replaced.
Electican has checked the wiring from the boilers socket to the fuseboard and thats fine.
They said it could be the wall stat. Which it cant be as its a new one fitted 3 months ago. And been checked by heating engineer.
If you isolate the boiler by switching it off at its source the rcd wont trip from anything else
So washing machine. Tumble dryer and ketttles wont trip the rcd.
Anyway technical have basically said everything that can go wrong has been replaced.
My engineer has ordered a complete internal wiring loom for the boiler to rule out a wiring problem to plugs and sensors.
The only other part is the pump which i feel should also be replaced as its a commen fault with tripping rcd units.
Problem i have is its intermittent. So will work fine for days. Possibly months then start tripping for no reason for a couple of hours. Or for a day.
Yesterday it wouldnt work all day just kept tripping the rcd. No faults on the boiler front. Today after switching it back on for the first time since it was tripping so just left overnight its fired up and giving water and heat. Very puzzling and very frustating as this boiler has been giving me problems since year 1.
Forgot to mention its not installed on ground level. Its on an upsairs wall in the airing cupboard away from damp with a 3ft flue to an outside wall through a cupboard. Flue faces north. The inside of the boiler is clean and dirt free. No corosion signs and no water damage and condensation damage inside the unit.

Really need a bit of advise on this one.

Thanks.[/quote]

 

[Andyshaun]

hi, picked a job up today from a landlord saying gas fitter been out and blamed faulty electrics for RCD tripping so went out to investigate. Apparently this has been going on for 4 years since it was installed. story so far.

1. boiler fitted 2008, trips RCD in cellar out roughly once a week.
2. installer comes back out and says boiler is fine, electrics are at fault.
3. Electrician comes out (not me) and says wiring & RCD are fine, boiler is at fault.
4. installer comes out again and gets in touch with Alpha, who advise him to alter the flue.
5. boiler runs much better, occasionally tripping RCD. gas installer blames electrics again.

At this time, I will point out that the lady is 96 and lives alone so has to ring for someone to re-set the RCD every time it trips.

6. electrician comes back and installs an RCD unit next to the boiler, to stop the one in the cellar tripping, and to make sure that nothing else is causing the trip.
7. same problem but now boiler trips new RCD occasionally, usually when windy.
8. gas installer disappears of face of earth, and boiler is long out of guarantee.
9. Last week, new gas fitter went out and serviced boiler and said he could not see a fault or see any signs of water near the electrics.
10. I was called out today and tested the RCD which is working fine, so there must be a problem with the boiler.

I really don't want to go back to landlord and say "its a fault with the boiler" without a possible reason, as this poor lady has spent 4 years being passed back and forth, so would really like to help her sort it.
Please note I am a registered electrician and will not be carrying out any work on the boiler, I would just like to be able to offer advice to a solution to this ongoing problem.
Had the exact same problem with two he33 it's a bad design fit some flue canopies to protect from the rain etc never had a problem again
cheers, Royce.

 

[Andyshaun]

hi, picked a job up today from a landlord saying gas fitter been out and blamed faulty electrics for RCD tripping so went out to investigate. Apparently this has been going on for 4 years since it was installed. story so far.

1. boiler fitted 2008, trips RCD in cellar out roughly once a week.
2. installer comes back out and says boiler is fine, electrics are at fault.
3. Electrician comes out (not me) and says wiring & RCD are fine, boiler is at fault.
4. installer comes out again and gets in touch with Alpha, who advise him to alter the flue.
5. boiler runs much better, occasionally tripping RCD. gas installer blames electrics again.

At this time, I will point out that the lady is 96 and lives alone so has to ring for someone to re-set the RCD every time it trips.

6. electrician comes back and installs an RCD unit next to the boiler, to stop the one in the cellar tripping, and to make sure that nothing else is causing the trip.
7. same problem but now boiler trips new RCD occasionally, usually when windy.
8. gas installer disappears of face of earth, and boiler is long out of guarantee.
9. Last week, new gas fitter went out and serviced boiler and said he could not see a fault or see any signs of water near the electrics.
10. I was called out today and tested the RCD which is working fine, so there must be a problem with the boiler.

I really don't want to go back to landlord and say "its a fault with the boiler" without a possible reason, as this poor lady has spent 4 years being passed back and forth, so would really like to help her sort it.
Please note I am a registered electrician and will not be carrying out any work on the boiler, I would just like to be able to offer advice to a solution to this ongoing problem.



Had the exact same problem with two he33 it's a bad design fit some flue canopies to protect from the rain etc never had a problem again
Andy



cheers, Royce.