My central heating needs daily top ups through the filling loop.
I checked the radiators and cannot find any sign of a leak, the rads don't even need bleeding after a top up.
Any clever tricks for finding where all that water is going to?
plastic bag over the PRV release see what it does.
what pressures in your expansion vessel.
Does it sound hollow or dull when you knock on it /
if your losing as much as you are with no visible leak i expect your expansion vessel may be fill and the PRVs triggering - but youll need to do some diag to prove.
Any clever tricks for finding where all that water is going to?
If you can work out what the inlet/outlet valves to the radiator and hot water system are, close them and re-pressurise the boiler. If the pressure still falls, the problem is in the boiler. If it holds, then suspect the house pipework.
We had similar late last year, there was a seal failed in the bottom of the main heat exchanger because of poor installation during a previous repair, although that was fairly obvious as water was weeping out of a union. Could be all sorts of things.
Sounds like the expansion vessel in the boiler has failed, common problem. Confirm it by putting a bucket under the drain pipe from the boiler outside. If it fills up that's where your water is going. The vessel may just needs re-pressurising or the bladder inside may have failed.
Well it definitely seems to be the pressure vessel.
My system has an external one, I have drained it off and then pressed it up to 1.5bar with my track pump. (It's got a schrader on the top).
I'll see what happens.
If it does drop off again then I new vessel is about £50 and it looks a straight forward to swop out.
Thanks for all your help.
Are you sure it is a system leak somewhere? My heat exchanger went and was giving the same "daily top up" problem. Tried the balloon on the pipe outside (no water in there) and also isolating the heating.... which confirmed that it held pressure. Plumber put sealant in (not Stans) but to no avail in the first instance.
Remove any covers you might have over your radiator pipes and wipe away any dampness on the pipe with loo roll. If you can get down then lie there and run your thumb gently around the pipe where it meets the valve nut. If that's wet then things might just need tightening up by a plumber.
It might just need tightening up with a spanner.
Use blue center feed roll for leak detection. It obviously changes colour when it's wet.
I have heard of people adding aftershave to the system and smelling around the rads if the leak is in the void
We had this and it was a porous heat exchanger on a nearly new boiler. Water was flowing through condensate trap and out of the condensate pipe. We couldn’t see it as it empties into a sink outlet. When the pressure vessel failed on a separate occasion it exited through relief valve and was obvious
Well after pumping up the expansion vessel yesterday, it has dropped again but not quite as much so quickly.
Changing the PV looks simple enough but jobs like that can easily go south!
posting, just so I can find this thread again (no favourites anymore?)