Boiler help please, not sure what's going on...

[Walserwasstrange]

Wonder if @PigleJjohn is around or anyone with boiler knowhow. Have a combi, Worcester Bosch Greenstar I JuniorCurrently, coming up to ten, just running hot water because it’s summer. A few days ago, noticed a slow drip of fluid from base of the boiler at the side, running across to other side. Turned it off, after about two hours the leak stopped.

Called in boiler engineer, he said probably from torrential rain earlier in the week, he serviced it including pumping up the expansion vessel. Prior to this, pressure was level and stable, had some issues when the heating’s running, sometimes had to top it up, but not otherwise. A couple of hours after he left pressure dropped to zero. Topped it up but steadily dropping again, gone from around one to zero in about two hours.

Wondering if anyone has any idea what the issue might be?
Will call the engineer but have had issues in the past, one engineer took the boiler apart – literally - for service, claimed it was broken/unfixable but couldn’t say why, tried to sell me a new one. Got a second opinion, turned out he’d not serviced it properly. And after that it was fine. This is a new guy, seems trustworthy but worried he may have caused the problem.

Meant to say @PigletJohn

My guess - the expansion vessel is faulty and has leaked out all of its air. That will make the pressure in the system go very high when it first fires up. To alleviate the problem the pressure-relief valve will be triggered and some water will shoot out - that should shoot out of a pipe on the outside wall, but it could also be the reason why you noticed some water on the base of the boiler. But now there's less water in the system and when everything cools down the pressure will be too low.

Boiler man probably tried to cure the problem by reinflating the expansion vessel, which is just a big balloon in a tin. But if I am right then the expansion vessel is beyond repair and just needs replacing.

We had a Worcester Bosch (not a combi) with a similar issue, slight leak, drop in pressure and it turned out to be a leak in the cast-iron heat exchanger and was beyond repair (no parts available - it was about 15 years old)
We had to have the boiler replaced.

Is it easy to check whether it's the EV or the heat exchanger? The boiler guy couldn't find any signs of leaks inside the boiler.

Thanks Mariel btw, I think if it's the EV it's going to be a headache, it's one of the models where it's at the back and I think very difficult to replace? Also wondering if it could be, might be very expensive? Was worrying that maybe needed a new boiler so trying to weigh up cost of repairing this one, if possible, versus a new one. I did go outside an check the PRV for dampness, wiped kitchen towel round it but not even moist - although it's hot so could have dried out.

Twoleftsocks could well be that too, sorry for you having to do that, I wondered if it was too good to be true when the engineer said it had at least 3 to 5 years left on it! Did you buy another WB?

I noticed they have a special offer on installation with all the trimmings but not sure how reliable they are now. Two of my friends have had ongoing issues with theirs, bought more recently than mine, one had her expansion vessel changed twice and still had to keep topping hers up. She has a Vaillant now and says it's better but the boiler guy says Vaillant are worse than WB. Also had people plugging Intergas recently but never heard of them.

But at least it sounds as if it's unlikely to be a leak somewhere in the system not sure I fancy trying to work out where it might be if there was!

I could see ours was leaking from under the boiler itself. (I put some kitchen paper towel so I could see where the drip started)
It was replaced with another WB that comes with a 10 year warranty (if an accredited engineer services it) reckon it might see me out!

@Hannahcolobus thanks, the bleed valve's the bit on the side of the radiator? I checked the bottom valves but didn't check those, so I'll do that. I don't think I've got a leak but possible. The pipes were all new when the boiler was fitted, had an old system with steel pipes and totally replaced everything, so hoping they're still okay.

If the boiler has to be replaced can it still be plugged into a standard socket? There's no spur where it is in the kitchen, the installer just used a socket next to it - the kitchen's due to be redone and planning to rewire when that happens but won't be until next spring. And not clear whether a socket can be converted into a spur, and if so would a boiler engineer be able to do it? I use a local builder, he's reliable, and he sorts out stuff when he does work but his guys don't work separately.

And Twoleftsocks - good to know, the recent reviews for WB seem very up and down, can't work out if that's the luck of the draw or whether some models more reliable than others. I tried to contact them once but they couldn't find me on their system, so I gave up. And they no longer allow you to search for local installers on their site, looks as if you have to book one in blind. Did you use their service to find your installer?

No! I used a local plumber/heating engineer and by chance he was accredited with WB.
(I had used him before to service the boiler)

Twoleft how did you find them/know they were reliable?

So far I've had:

• an installer who did a good job but whose assistant drilled through electrical circuits, and put a radiator in a position that made it impossible to close the room door. He moved it but left gaping holes in the wall so I had to redecorate and when I left messages about the electrical circuit never got back to me. So had to pay for an electrician as well

• I had a plumber to fix a water leak who put the wrong connector on the pipe, so my house flooded in the middle of the night

• The boiler engineer who spent two days dismantling the boiler and claimed it was kaput when it wasn't.

• the plumber who fixed a leak and told me that even though it was still dripping it would clear up soon, it didn't

And now the service guy is not responding to my message re: the boiler not working. I had a decent boiler/plumber person in between but he retired and seems really hard to find someone reliable to replace him.

That's not to mention the people who gave me incredibly over the top quotes or told me things that when I checked were just wrong. I think I'm a bit cursed when it comes to finding decent plumbers/boiler engineers! All of them were recommendations. I'm not sure if this kind of thing's common and I know there must be other decent people out there but how to find them?

@Hannahcolumbus it's coming up to ten years old.

op aren't most Worcester boilers guaranteed for 10years?

Ours needed repair recently, leak, losing pressure, 10 years old also... "flow turbine perished - replaced" is what it says on our repair docket.

Choice of plumber / engineer was (perhaps bizarrely)
He is very local (useful in an emergency)
His vans were very clean (may mean he pays attention to detail)
Initially required a service and he seemed polite and competent.
That was it. Maybe I was fortunate.

Mumwon this one was for five years, the new ones I think vary depending on installer.

@Hannahcolumbus the socket is part of the circuit for the kitchen which I think is a ring main? Does that sound right? I had an electrician in to rewire upstairs before redoing the bathroom and upstairs' rooms, he also put a new junction box in the kitchen because the old one looked dodgy. He didn't mention the boiler connection. And the people who installed it and the engineers I've used since are all Gas safe, I checked their cards and their registration online, and I got the relevant paperwork back when the boiler was installed. And the electrician also had all the appropriate credentials which I also double checked. So I assumed it was okay but then came across something in the last few days when I was checking what the current fault might be that made me wonder about the connection. The Vaillant installer manual says preferably a fuse spur but doesn't insist. Is it a new Part P thing? Can a boiler engineer run a new circuit for a fused spur or sort out an electrician to do it? It's hard to get one in to do one job I've found, so always had to bundle stuff.

The engineer who serviced it said a new one could be plugged in and switched to a spur when the kitchen's redone. But sounds as if he was wrong?

Beyondmywits a flow turbine is new, will have to look that up thanks.

a single socket can be changed to a switched fused connection unit with flex outlet with total ease.

I don't know why you shouldn't use a plug and socket. Some weird gas rule? The instructions are likely to say "a means of isolation with a 2 mm contact separation on all live conductors" or something similar. A switched socket and switched FCU can both do that (there are a few old single-pole switches around) BUT as many electricians point out, if you pull the plug out of a socket, you have a contact separation of 50mm, 100mm, 300mm, 1000mm, depending where you put the socket down.

If the instructions say that the isolation must be capable of being locked off while worked on (not often specified on domestic appliances), some (possibly all) FCUs are capable of having a padlock through the fuseholder when opened.

@Walserwasstrange "Is it a new Part P thing? "

definitely not.

The Requirements section of Part P is 28 words long and does not say that.

Why does it need it?

Is there a Building Regulation?

@PigletJohn I was wondering that too. Thanks for information on fused spurs btw, appreciated but don't fully understand isolation or what it is really!

@Hannahcolubus, I thought about WB but they have a fixed price which is over 300 I believe, from talking to them before and from looking on WB reviews online, and so if they can't fix it that's a fair slice of cash towards a new boiler.

I think a local independent might be less pricey as can quote for repair or say if repair not feasible so only have a standard call-out fee which I think would be a lot less? Could the engineer I used have missed one of the things it could be? Should I try to use him again or does missing it mean he may not be reliable?

But good to know you think 10 years isn't beyond hope. I was really hoping it could survive a bit longer, have had quite a few unexpected expenses lately so trying to be careful with money.

Also sorry probably one question too many but does the fused spur have to be switched or unswitched or doesn't it matter?

@Walserwasstrange if you’re anywhere near Stoke-on-Trent I can recommend a really good, reliable firm. My parents have just had their 20ye old boiler replaced and the company were really good.

@Hannahcolobus thanks, sent him a message yesterday morning but haven't heard back. I didn't realise about the difference between installers and people who are skilled at repair, so that really helps.

Will look for repair specialists, and thanks for the tip about age of boiler, is there anything that can't be fixed/replaced? Or that's likely to be too expensive to bother?

Also heard from a friend who had a similar problem after a service and was told it was a blocked condensate pipe so I will add that to my list.

Maitlandgirl thanks, not in that area but appreciate the offer.