Worcester Bosch Greenstar 29 CDi Classic ErP - new boiler losing pressure when heating off

I think that is pretty conclusive

 

What sort of ground floor do you have - is it suspended wood floorboards/ shipboard (how old is the house)? Any idea is there's a crawlable void under there?

It is clearly a significant leak - not exactly pishing, but a pretty fast drip I'd have thought. There are such things as leak sealers you can add to your system water, but I'd personally be reluctant to go that route - but I haven't had any experience of them.

What do peeps think? Perhaps there's nothing to lose by trying - I mean, the leak seems to be under the ground floor where it ain't causing damage and the worst that'll happen if it reappears is that the pressure starts to fall again.

What do people think?

Obviously better if the actual leak is traced and repaired, so try and get BG to come out and sort it first - and I like Mr Rusty's advice. Also, it'll be fascinating to see how they go about tracing where the leak is - will they be as good at it as you?! Keep us posted

 

You need more than leak sealer to solve his leak, pointless bodging it, needs a proper repair.

 

It's a pretty conclusive test, DJ - the isolated boiler holds its pressure, but it's clear the isolated radiator system does not (the pressure reading falls immediately you open a valve, so that shows that the rad system's pressure had already dropped).

The leak is significant - a cupful or more of water each day.

It is most likely to be under the ground floor 'cos you don't have any visible damp patches inside the hoosie. Of course, that part ain't conclusive - the pipes might run up a fairly well protected void to the next floor, so water could be trickling down there and under the floor...

Any idea how your pipes run? Usually the path is fairly obvious - like straight up from the boiler to the ceiling?

How do the ground floor rads get their flow - are you sure the pipes come from under the floor and not out from the wall (in which case they probably drop down from above).

Anyhoo, I'm surprised the boiler keeps running on 'zero' pressure - if it had a digital gauge, it would almost certainly tell the boiler to shut orf (mine does, at 0.6bar...)

But, as long as your boiler works without stupid noises, you can use it until the repair - but shut it orf if it starts to 'bang or grumble). Longer term use ain't good, tho', 'cos you are introducing fresh aerated water (why isn't that spelt airated...?) each day, and with that comes the risk of internal corrosion to your rads in particular.

No, it's nothing to do with how the boiler was set up.

One Q - do you have drain cocks for your system? Do they stick out through the outside wall? They aren't dripping, are they...?

 

If the two pipes (flow and return) that supply your upstairs are visible as you say, then, yes, you can isolate the upstairs. It will mean cutting into both these pipes to do so (and probably fitting full-bore valves so's it can be turned back on or off when needed).

That thermal camera is interesting. However, I doubt it'll help since the amount of leakage is slight and will cool very quickly as it escapes. But, I simply don't know.

Will you be able to hear the leak? No, I doubt that very much - it's far too slight.

If leaks are covered by the BG policy, then call them out. You can always stop them if they threaten to pull up floors...

 

with regard to general house insurance, I doubt they will cover for a "repair" caused by "wear and tear/age" - particularly if the location isn't identified.- and this is probably the line they will take. I had a policy 10 years ago that I needed to claim an accidentally damaged shower tray - something caused the drain area to break away, and they at first said "wear and tear" no cover. I had to push to get the claim accepted under accidental damage. In all honesty, would never make such a claim again, too much hassle - anyways I digress -

If you find the leak and there is an obvious cause - damaged by flooring/carpet contractors, you accidentally stuck a nail through it, etc, then you might get accidental damage cover, but you'd have to find it first.

If you have BG cover for central heating, I think that's your best bet.

 

Drain down, disconnect pipework from boiler, dry pressure test & go around with soapy water checking joints for leaks,sadly it isn't done by many today.

 

That's all good and well - if you have good access to the pipes.

Which the OP does not...

 

Well I would have,even more so with using pre-exsisting pipework,it hightlights any potential problems,& has saved me a lot of grief in the past by doing so.
Some plumbers do it,but others consider it old fashioned, time comsuming & not needed.

 

Which is a pain in the rear.

 

I would not expect a plumber to carry out a 'dry' test, since this involves pressurising it with air up to, presumably, 3 bar or so - bludy dangerous I'd have thought (air compresses a lot, so that would be a hell of a lot of stored energy should a fitting come apart...)

However, I would expect a plumber to monitor the wet install after being commissioned - I'd say it's actually part of the commissioning process when new pipes and rads have been added.

How was the install left after it was done - was it filled and pressurised? Or left empty - and you've only discovered the 'leak' since moving in and topping it up?

Anyhoo, to answer your Q in a simple way - if the leak is on part of the new system, then - yes - the installer is liable. I can't see any doubt on that.

So, really, if you cannot tackle this job yourself and need to call out a plumber, then the original guy is the one to call - but obviously be prepared to pay him for his time if the leak is on an old part of the system. Fair do's?

On the other hand, if your BG boiler insurance policy covers leaks, I'd be inclined to call on them first.