Boiler service, then boiler breaks

Hi all,

Had a annual boiler service this morning by a local gas company. No issues identified (boiler is a relatively new Worcester  28CDi Compact combi). We didn’t check everything was working prior to them leaving (busy with calls etc), nor AFAIK did they.

Few hours later we realised the heating wasn’t working (but hot water was). Boiler controlled from Nest, Nest working but boiler not firing.

Called company back. While engineer was en-route, their office emailed me to say that if the cause of the boiler fault was found to be separate from the morning visit, the re-visit would be chargeable.

Engineer spends ages trying to fix it, initially thought it was the Nest, spoke to senior engineer, eventually identify that a relay on the control board has gone, and the board will need to be replaced – expects board will be a couple hundred, plus labour.

Engineer was of opinion that its just coincidental that the board failed today, or that it was on the verge and the service tipped it over.

What do people think about this? While it seems unlikely they blew the board on a service, I can’t get away from the fact that prior to their visit I had a functioning boiler and after it I didn’t, so don’t love the idea of having to pay for the visits and repair.

Another factor is that we kind of need it repaired ASAP so don’t want to spend ages back and forthing with them…

Thanks!

Even if it wasn’t coincidental what would you do? There’s really no way of pinning it on them so can’t see them entertaining taking responsibility.

If its an elec failure i cant see how a service would cause a component failure

Makes you wonder really – if it isn’t broken, then don’t have anyone mess about with it.

I had a fairly similar incident a couple of years ago – the expansion vessel went about an hour after the engineer left. It cost me about 400 quid I think.

I don’t bother getting the boiler serviced any more.

Me neither, ours is 23 years old now so if anyone touches it it’ll probably break, or they’ll condemn it because they can’t be arsed to find parts.

If that happened to us I’m sure the plumber I use would repair free of charge. Get it sorted then find another plumber, unfortunately they’re like every profession, 99% are honest. I live next  door to a plumber who I wouldn’t use, his solution to every problem is “rip it out and new boiler”. Good luck.

If you use the Worcester own technicians its fixed price repairs and a great service

Its probably a coincidence that the boiler failed

I’ve watched the service / chatted with the same service guy a few times on a similar Worcester in our old house. I can’t think of anything he did that could be blamed for blowing a relay. They really aren’t doing anything invasive on a modern boiler. Basically checking pressure of expansion vessel, cleaning filter, running it up to stable temperature and measuring flue gases. It was only older boilers where they were stripping down and cleaning burners etc.

Our boiler is 20 years old now and my good friend who is a 30 year gas engineer won’t service it because he said it’s likely that tinkering with it will cause something to break which will be an expensive repair so to just leave it alone until it breaks.

Obviously not the same situation as a newish boiler but makes you think that they are quite fragile devices.

It’s probably a result of something that they have done but you will never be able to prove it, and they will never admit liability because they know you can’t prove it.
Disclaimer. I sell boiler spares and boilers.
I have also had my own WB combi part and have successfully repaired it.

It will be a result of doing something else for example bleeding the pump and a jet of water has found it’s way down into the PCB . Or whilst opening the combustion chamber a lump of soot has dropped down into the PCB , as an example.

Then it’s done something to a relay , when it’ been switched on.

If you are in any way competent open the front and check if you have power to the pump with one of them pens , or pull the power cable and see if it goes live when you turn on the CH.

I repaired my PCB about 8 years ago , the fan relay failed so I bought a new one for pennies and soldered it in .been fine ever since , and my combi is over 20 years old .

How sure are you that they are able to diagnose the issue? I really don’t believe in coincidence at all , it was perfect , someone has come in to fiddle around and now it’s broken.
Won’t be malicious , but also won’t be unrelated.

If you’re really clever you might be able to hot wire the pump to run off a separate feed , but I don’t know if the pump feeds back to the board it’s spinning or not depends if it’s got 4 or 5 wire’s like a 3 way valve which feeds back to the boiler .

Same here, old 25 year boiler – little Baxi Solo 30. I look after it where I can. Fan sometimes get’s noisy, a squirt of Finish Line Ceramic chain lube has sorted it for 15 plus years. Spark not working, so opened up combustion chamber/heat exchange, and cleaned up gas chanel and electrode with electricl cleaner/emmery paper on the metal bits. Then the gas valve solonoid magnet went wonky so got a whole new gas valve for £30 and just replaced the magnet (magnet alone wasn’t available).

Kettling and noises have been fixed by draining the system (open vented not combi) and then putting in a load of inhibitor.

I have a CO2 monitor near the boiler anyway. Boiler is ticking along quietly and not costing much in gas each month.

I suspect, if I go for a service contract etc with a new gas/leccy contract, the engineers will say ‘nope’.

Funny this , as I’m having issues with our boiler albeit an oil burner, had serviced etc all ok , 2 days later no hot water , turns out micro switch playing up on diverter etc , changed that and then diverter started leaking , changed seals etc , 2 days later starts leaking again , came out again and suddenly needs new automatic air vent as cant bleed ? , did that etc , get up today to a few drops of water on counter top and then a email invoice of £452 !! …

He does keep commenting that it needs replacing etc , and I’m looking at the best part of 5k for like for like ! ..

If it’s a relatively new boiler is it not in warranty (assuming you have got it serviced as required to keep the warranty). 

I suspect powering down the boiler electrically whist working on it and then re starting / re booting the PCB might cause this.. electrical and electronic components do just fail without much warning from experience.

WORCESTER BOSCH 8748300910 G/STAR CDI COMBI/SYSTEM CIRCUIT BOARD (161TK)

If you’re really lucky it’s just over £100 for the new PCB

I also think you can fit it yourself as it’s plug and play .

This is on a next day , incl Sunday delivery, from Screwfix

Thanks all.

Singletrackmind – thanks but I’m not certain that’s the right board. This is the boiler we have :

https://www.plumbnation.co.uk/worcester-greenstar-28cdi-compact-combination-boiler-natural-gas-erp-10-12742

And from the boiler code, eBay shows these two PCBs, both say they are for this boiler so not sure how to work out which is correct (I have messaged seller)

https://www.ebay.co.uk/itm/125869793042?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=59gro8ilrds&sssrc=4429486&ssuid=hdT4SCQsRD6&var=&widget_ver=artemis&media=WHATS_APP

https://www.ebay.co.uk/itm/125869802707?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=59gro8ilrds&sssrc=4429486&ssuid=hdT4SCQsRD6&var=&widget_ver=artemis&media=WHATS_APP

Thanks!

I also think you can fit it yourself as it’s plug and play .

On a gas boiler. Inside the casing. Are you quite sure.

On a gas boiler. Inside the casing. Are you quite sure.

It’s only gas side of a boiler that you’re not allowed to mess with unless your certified

And the boiler case forms an air tight seal therefore you aren’t allowed to take it off.

And the boiler case forms an air tight seal therefore you aren’t allowed to take it off.

Are you sure? My Worcester from 2021 is not gas-tight around the exterior casing, all sorts of holes punched into the steel with non-gasketed fittings and windows.

But the front case you need to take off to get to the PCB is almost guaranteed to be a seal between the room and the gas parts of the boiler, and so requires competency/certification to remove.

https://www.gassaferegister.co.uk/media/1449/who-can-legally-work-on-a-gas-appliance-factsheet.pdf

Both my work colleague and my nextdoor neighbour had boilers fail within hours of a service. In the case of the neighbour it was a part fitted back incorrectly and it squirted water all over the pcb. That cost him £400 with a different plumber as the original one refused to come back for free to look at it – never managed to claim. With my colleague it was the classic case of an old boiler being ‘disturbed’ by the service and breaking. He didn’t feel it was really the service guys fault as boiler was 20 years old even though it was caused by him so just paid up.

I used to have a 30 year old boiler which was incredibly simple inside – I once watched a repair guy and he was absolutely useless, heavy handed and clueless as to simple things like certain sensors he told me had failed which was causing the constant shut downs – except it didn’t have one as it was too old as I’d checked already.He couldn’t fix it and said I’d need a new one – I took it to bits after he’d gone found the electrical short that was causing the issue, fixed it, changed the thermocouple, put on a new seal and it ran fine for the next 5 years, serviced by me totally illegally but 10 times better than anyone I paid – I did put a good quality monoxide sensor nearby.

Now I have a fancy new boiler 2 years ago and it has a 12 year warranty conditional on a service every year. The guy that does it literally takes the case off, hoovers it, plugs a laptop in and then asks for £75 plus vat!   He’s a nice bloke but admits its the easiest money he makes in a day

We had one very similar and that board was in the sealed side. Bit of a pain as you needed someone qualified even for basic stuff like fitting a wired room stat that used to be externally accessible on older WB. The stat cables exit through sealing grommets.

It might not be, but don’t assume just because it’s not anything to do with gas that you can do it as sometimes the case is sealed.
obviously will be checking combustion after fitting the board just in case it is programmed wrong… I had the wrong control fitted to a brand new boiler once!

Also I appreciate that there are some terrible installers out there, having sat on courses with them I wouldn’t let them construct anything with Lego let alone gas pipes, electricity and water. But that is the problem with commercialising the training, people won’t go to a training centre that is known for being strict (or doing it correctly as it should be known), so the centres make sure most people get through.

Funny this , as I’m having issues with our boiler albeit an oil burner, had serviced etc all ok , 2 days later no hot water , turns out micro switch playing up on diverter etc , changed that and then diverter started leaking , changed seals etc , 2 days later starts leaking again , came out again and suddenly needs new automatic air vent as cant bleed ? , did that etc , get up today to a few drops of water on counter top

Not a Firebird boiler, is it?

And the boiler case forms an air tight seal therefore you aren’t allowed to take it off.

Not on mine it isnt, not the part if the case that the circuit board is in anyway.

I once watched a repair guy and he was absolutely useless

I had a back boiler that was almost as old as I was. I used an old boy for servicing whom my grandparents knew from like the war or something. When he retired, the company sent out a young lad whose opening gambit on seeing it was “what the **** is that?” which did not exactly instil confidence. I serviced it myself for a couple of years before fixing it with a new house, the gas side of things was a three-way valve and a locking nut. Isolate supply, disconnect pipe, hoover out, stick a tea light under the chimney, reconnect, any gimp could do it.

A service is likely to have the board exposed, if the plumber touches it (especially with a nice synthetic fleece on) it’s likely to get an electrostatic discharge which could kill the board. I’d use that as a stick to beat them with.

I had almost the exact same situation last year. House has a newish boiler when we moved in but we forgot to set up an annual service so three or four years went by without a service. Got someone out last January to give it the once over but it had been working fine, and was around 6 or 7 years old.

Engineer said that heat output was down and possibly putting a new heat exchanger in would improve it, up to us. I said OK so they ordered the part and came back a week or two later. After fitting, absolutely no difference to the heat output so £200 down the drain already. Engineer says they’ll turn the flow rate down a bit on the hot water so hopefully it will be hotter (bear in mind we had no problem at all with performance before the service).

Boiler is in the loft so if no one happens to be going up there it isn’t seen. I head up to put some junk up there and notice wet under the boiler, but assume its the flu-roof interface that sometimes lets a little rain in when there’s a downpour, so a couple of weeks go by before I realise the system has stopped working. Go up again and pressure is zero, and the boards under the boiler are soaking wet. Realise its leaked all the water out.

Call boiler company, this time they send a different engineer out. He’s up there a fair while and decides the problem is the sump gasket is leaking. I’m sceptical. Says he has to order one, so wait another week. Comes back to fit it, and takes an entire morning, the invoice is about £500. He ended up taking the boiler off the wall, cursing and swearing, because apparently it also needed a proper gasket on one of the unused flu blanking plugs, his opinion was it wasn’t installed properly.

At this point I’m grinding my teeth a bit but these things happen, especially in January when the bank account is overdrawn and its cold. So, not wanting to think about boilers for a while no one ventured up into the loft for a couple of weeks. Until the heating stopped again. Up I went, floor under boiler completely soaked and pressure on zero. Boards were starting to curl up they’d had so much water in them, and I noticed there was a bit of a stain starting to appear on the landing ceiling.

Cue cross email to boiler service company’s complaints inbox. We’d gone from a totally fine boiler that was a bit overdue a service to one that pi$$ed water out and paid for a heat exchanger when the old one was perfectly fine, total bill so far almost £1000.

This time they sent a different engineer who seemed much more clued up, turned out the main water vessel had a crack on the weld, hard to spot. They took off the invoice for the previous visit, and ordered a water vessel, and they’re one of the more expensive parts on a boiler. He advised it was a toss up between that and going for a brand new boiler.

These things happen and I’m a reasonable person, I’d even use the same company again for a service, but I’d also had to swallow some other emergency payments last winter including a £2k vet bill and an expensive MOT failure…

if the plumber touches it (especially with a nice synthetic fleece on) it’s likely to get an electrostatic discharge which could kill the board.

I’m calling bobbins on this.

I’m far from an expert but I’ve worked with electronics, if you include hobbyist and academia, for about 40 years. Number of items killed by ESD, zero. I’ve had countless computers in bits and whilst motherboard failure does happen it is (outside of Capacitor Plague era) vanishingly unusual, I could likely count them on one hand. You could take a PC PCB in one hand, rub a balloon against a cat wearing nylon socks with the other and it’d probably be fine.

So what are embedded systems (boilers, cars etc) doing differently which makes them so prone to failure? An over-reliance on CMOS chips? Just a catch-all for “I don’t know what’s wrong with it therefore Electronics”? Cheap crap sold at a premium? Hostile environment (water, steam, grot)? Something else? It seems rather unlikely to me that a (grounded) boiler PCB would fail because someone touched it, unless it was shite to start with.

Not a Firebird boiler, is it?

Utter pieces of shite them. We had one here when I moved in…. Along with two complete spare units In the garage inherited by previous owner.

Not sure what was going on. Sold the whole lot to somechap for a couple hundred quid after the first break down. Fitted a grant combi outside and that was 15 years ago. Still trucking.

Hostile environment

Probably. High number of thermal cycles in their lifetime.

Unfortunately it does happen.

I had a WB Ri the other day that I cleaned out, which means removing the fan assembly. I always handle these fans with care as they are packed full of electronics. After replacing everything to test, the fan decided to pack up there and then for no obvious reason.

Even if I replace a PCB on these I still like to do a combustion analysis.

Same happened to me on a very similar boiler that was about 6 years old. When we moved in we got it serviced, and miraculously the control board blew and the boiler was beyond economic repair. It’s my oppinion that the electrical fault wasn’t actually diagnosed as the gas fitter is out of his comfort zone with electronics, so a control board etc is often blamed prematurely. But what can you do, they won’t fix it so I ended up having to get a new boiler. I’ve had some absolute shit3 tradespeople who think they can just pull the wool over people’s eyes.

@duane

“relatively new”?  5 year warranty now.  10 if installed by an accredited installer – id’ be talking to WB

https://www.worcester-bosch.co.uk/support/product-guarantees

Basically checking pressure of expansion vessel, cleaning filter, running it up to stable temperature and measuring flue gases

Our boiler is 8 years old now.  I tried getting the installer back after a year to service it and he said he didn’t recommend it.  Theres almost nothing that they usefully do on a service now so to save my money.  A C02 alarm for safety – the boiler software will spot any faults basically I think (it’s a Viesmmann storage combi.  the one thing he said I should do is check the expansion vessel with a bike pump and make sure it’s at the right pressure every year or so.).

My WB PCB is not inside the gas tight seal .
It sits directly behind the controls on a plastic hinged plate with air vents underneath. Lift the front drop down cover. Unscrew 2 electrical screws and it pivots out towards you.
Removal is tricky as the wiring is tight and the connectors hard to access

On this boiler? It was as you describe on our 28 CDI 1999 vintage, but not on the one similar to the OP’s.

I’d echo other people’s experiences above

I have had an annual service to maintain 10 year warranty

On three occasions something broke the same day the engineer had serviced it. He says it happens when testing but not covered under warranty.

Now it is out of warranty I just leave it to work, and will pay for repairs when a part breaks.

Previously when making small talk with gas engineers, a number o f them have 40+ year old boilers in their own homes. When I asked why, considering they could install any boiler they wanted, the reply was always the same.

Older boilers were built to last, and when a part eventually does wear out, the part is usually available, solid metal, and low cost.

They put up with a slightly inefficient 40 year old design because of its durability. Furthermore, they don’t carry out annual services at home for fear they may damage something during the process.

And in answer to the service does nothing. We had a hot water resonance problem that WB tried and failed to fix (thinking it was on the water side). At the next service, the flue gases were showing as out of spec, and recalibrating the gas valve to fix that also cured the resonance.

My gas engineers annual service is to analyse flue gas for combustion (which is a diagnostic and can I dicate issues) empty the condensate trap incase there is sediment snd have a look inside for any obvious leaks. That’s it, for 80 quid. Literally the only reason I get it done is to maintain the warranty. As i understand it, Wb warranties mandate an annual service.

trail_ratFree Member

”Not a Firebird boiler, is it?”

Utter pieces of shite them.

I can’t disagree.