Falling pressure

[BigGar]

Hello

I have a combi boiler and am having to top it up with water every day. This has only occurred very recently. I have got some people in to have a look and no leaks can be detected anywhere. Anybody know why this could be happening then? Somebody has mentioned a possible problem with a pressure relief valve or an expansion vessel (?).

Any advice would be greatly appreciated.

 

[ChrisR]

Is there any sign of water at the pressure relief pipe which goes through the wall?
You didn't read the fixed messages at the top...WHAT BOILER is it, how old, any other problems etc. !
What range did the pressure gauge move over before the leak?

 

[BigGar]

Chris R

Thanks for response

1. It is an an Intesa combi Boiler (Gas). Not sure of precise manufacture number.
2. After topping up system to just over 1 bar the system tends to gradually fall back to zero. The drop in pressure starts to appear noticeable after 45mins or so.Eventually it drops to zero after approx 4 hours.
3. Yes a new radiator has been added to the system in the last week. Whilst this would initially stand out as a reason there is no evidence of water appearing anywhere near this radiator or between the radiator and the boiler. I would have thought that water would feel through the skirting board if this was a problem.
4. The system has historically needed topping up every 3 weeks or so. In that time it would drop from one bar to 0.5 bar. Recently the tooping up has been required more frequently.
5. The heating is firing up no problem. The rate at which the pressure drops seems to be SLIGHTLY more quickly when the system is idle.
6. An occasional drop of water can be felt at the site of the pressure relief valve outside.

Thanks.

 

[kevplumb]

if you can feel water at the prv it is leaking