DIY Doctor UK DIY Forums

Hi,

I hope someone can help, because my partner and I are baffled.

We just fitted a load of new radiators this weekend and refilled the system on Sunday. Now, we've done this before and we thought we knew what we were doing, but it doesn't seem to be working properly and we have no idea why.

There are 4 radiators upstairs and 2 downstairs. 2 of the upstairs ones are still turned off (the 2 new ones). The other 2 have been there for a year with no problems. The downstairs ones are new.

The system filled with no apparent problems at first, a couple of fittings leaked a tiny bit, but we tightened them up and they were fine. Then we noticed the pressure wasn't holding.

All the radiators were filling and bleeding fine, execpt the big one downstairs, which doesn't seem to be filling right and is making a funny noise.

Things we've tried:
- shutting off all the radiators except one
- shutting off all return valves and only opening 2 flows
- shutting off everything except the big downstairs radiator flow valve, radiator still doesn't seem to fill

in all these situations the pressure still drops, but there are no obvious leaks (though it's possibly my lovely new pipe under the lounge floor is just pouring water under our house as we wouldn't be able to tell. I have no idea why it would be leaking there though). Could it be something wrong with the boiler?

Any help would be very greatly appreciated!

Cat

Is it possible you have disturbed the piepwork under the floor when fitting the new radiators, maybe you have moved the pipe and there's a compression joint that has come undone - or a faulty soldered joint.

Basically - pressure ok before new rads fitted ? there's a leak somewhere.


htg

A further point to what Htg has said, if you have not bled all the air out of the system, and it sounds as if you haven't as some rads are cold, then any air circulating through the boiler will be bled off by it's automatic bleed valve which of course will cause the pressure to drop.

If you can't shift the airlock by turning off all the other rads (make sure it is all!) you need to disconnect a rad valve, and point it into a bucket. The high flow of water when you open the valve should force the air through.

A further point to what Htg has said, if you have not bled all the air out of the system, and it sounds as if you haven't as some rads are cold, then any air circulating through the boiler will be bled off by it's automatic bleed valve which of course will cause the pressure to drop.

If you can't shift the airlock by turning off all the other rads (make sure it is all!) you need to disconnect a rad valve, and point it into a bucket. The high flow of water when you open the valve should force the air through.

possibly leaking under the floor. the leaks you found were on your work? if so then it's very possible it's under the floor.

it'd be very bad luck but these boilers have been known to have leaky heat exchangers which will leak internally and the water go out of the condensate pipe, therefore you'll never see it leaking anywhere.