New boiler fitted but pressure keeps dropping

IvyFlood

Wonder if anyone can help/advise while we wait for the pros to come round tomorrow!
So a couple of weeks ago we had a new (Baxi) combi boiler fitted as our old one was leaking (we'd been smelling rotten egg). Boiler is in the bathroom.
After a week of it being fitted, the heating didn't come on and the pressure had dropped completely to zero. Topped it back up and tried not to think too much of it.
Until last night when I was woken up by the husband fiddling with it and he said it had dropped again. Topped it up and tried to get back to sleep. Heating didn't come on and it had dropped again!
Now we are aware that we've got this new boiler but our rads (and pipework) are original (1960s build) so we are looking to get the rads replaced as I'm not sure the boiler will be working as efficiently but surely this wouldn't cause pressure to drop completely?
Can't see any obvious leeks coming from upstairs and as far as I'm aware downstairs is ok too (though obviously can't check).
Got the same chap who fitted it coming round tomorrow but just wondered in the meantime if anyone knows what the problem could be?

neilmcl

Put some pressure back in to the boiler then try bleeding the radiators to make sure there's no air in them then check and refill the boiler again if necessary. If it's still dropping then get on to the person who fitted your new boiler.

Jeepers_Creepers

If you are losing pressure that quickly, then there's an obvious 'leak' or water discharge somewhere. It could be from the pipework, or it could be 'internal' from the boiler. Let's hope it's the latter.

Your plumber is coming out to check, and that's the way it should be.

One simple thing to look at - when you top it back up, what does the pressure then do when you turn the heating back on?

scottishblondie

Follow the above advice.  If the pressure continues to drop there must be a leak somewhere in the system and not necessarily at the boiler itself - for example we know we have at least 1 leaky joint under the floor and as a result we need to top up the system about once a month (1970s stainless steel pipes, which are resisting repair attempts).

AskAsk

either a leak in the boiler install or the central heating pipes.  hopefully the engineer can identify where the leak is, otherwise it may be difficult to work out where in the system the leak is happening if the pipes are ran under the floorboards.

Ectophile

Another thing that could be leaking is the pressure relief valve.  That valve normally leads to a small pipe poking out through the wall behind the boiler.  And it's not the same as the condensate pipe, which is supposed to drip.

IvyFlood

Thanks all for the replies. Husband had the engineer round yesterday while I was at work and they checked the boiler and rads and unfortunately it looks like a slow leak somewhere presumably on the ground floor. We have a suspended timber floor so they will have to cut a hatch and go under and investigate. We did have a hatch in the lounge but we covered this with wood flooring after we had the house rewired! Wish we'd checked the pipework but hindsight is a wonderful thing!

Jeepers_Creepers

Thanks for the update - could you let us know what they find, please, as these sorts of threads come up quite regularly.

Hopefully it's down to a sole joint that's failed, so it'll be an easy fix and there should be no reason to think it'll happen again.

roddydogs

Surely the first thing is to try a liquid sealant first, probably won't work but worth a try.

neilmcl

Agree with the above. I'd be wanting to give something like Fernox F4 leak sealer or Sentinel leak sealer a go first before going to the expense of taking up your flooring.

AskAsk

IvyFlood said:

Thanks all for the replies. Husband had the engineer round yesterday while I was at work and they checked the boiler and rads and unfortunately it looks like a slow leak somewhere presumably on the ground floor. We have a suspended timber floor so they will have to cut a hatch and go under and investigate. We did have a hatch in the lounge but we covered this with wood flooring after we had the house rewired! Wish we'd checked the pipework but hindsight is a wonderful thing!

there is equipment that can detect where the water leak is without lifting the floorboards.  it may be worth getting a company with this sort of equipment to trace the leaks first.