Central Heating problem

[Tom Sendall]

I have a 2 year old Baxi 105e Instant. About 4 months ago I noticed the system was losing pressure, alittle at first,then alot so I kept topping it up(the pressure went down to 0, then I refilled it to 1 bar (when cold)). There was no obvious signs of a leak (no damp patches on the ground floor ceiling and I accessed the sub-floor void several times - no leaks (its a two storey house with no pipework in the roof)), so was advised it may be a faulty overflow relief valve. I have been looking into the problem for a while, and today changed the valve, but the same thing happened - rads got hot, pressure went up accordingly, ORV let water out (when pressure got to above 3 bar) then stopped letting out water. However, I lost all pressure in the boiler again - but only when the rads were on - when the boiler is set to taps only the system does not lose pressure. Where can I be losing water from? Is it the boiler or the system? All rad's are getting hot with no cold spots.

Any ideas would be most welcome.

Many thanks, Tom Sendall

 

[corgiman]

do a search on expansion vessels

 

[gas4you]

Check that your filling loop is fully shutting off first, then if it is do as corgi says for expansion vessel faults.

 

[Tom Sendall]

Thanks for the response, expansion vessel it is then....

Cheers for your help

Highest regards, Tom