Combi boiler strange pressure rising problem

[DIYdabbler]

I recently drained my system by opening up one of the drain cocks downstairs, then repressurised my expansion vessel to just over 1 bar and then refilled the system up to 1 bar using the filling loop. I then bled the rads and topped back up to 1 bar again.

It generally works fine now except for the fact that I'm now seeing the pressure when cold creep up slowly, something like 0.1 or 0.2 bar each day. I checked the filling loop and it doesn't appear to be leaking. I can't leave the filling loop removed though as the non return valve between the boiler and filling loop is leaking, so the filling loop is stopping this water from escaping.

Any ideas what could be causing this gradual increase in pressure each day? Could anyone offer any tips on what I could check please? I'm currently having to release some water from the system each week to bring the pressure back down to 1 bar when cold, which obviously isn't ideal. Would appreciate any advice.

Thanks,
Steve

 

[Baxmax]

And the boiler is a............

 

[DIYdabbler]

It's a Potterton Combi 80 boiler.

 

[Baxmax]

Call Heateam you will be amazed

 

[bster]

put a new filling loop on (as it may be 'letting by' ) alternativly cap the end of the filling loop that connects to the cold mains, either way remove the loop, if the pressure still rises when cold (boiler not in use) then you may have a split DHW heat exchanger. Check for this by isolating cold water inlet to boiler - if the problem is solved then your quids in (or out ).

 

[kevplumb]

I can't leave the filling loop removed though as the non return valve between the boiler and filling loop is leaking, so the filling loop is stopping this water from escaping.

the loop should be removed to comply with the water regs


ohh yer in deep S**t mate

(gets off soapbox )

 

[bster]

regulation R.24,



hence filling loops that are stated as being an R24 filling loop conform to the regs but they also have to be disconnected from the mains to conform to other aspects of the regulation (backflow)

Kev is learning

 

[kevplumb]

cheeky young bloody upstart

 

[bster]

Thats what you want from your star apprentice though





............and I cant fall through the ceiling of the internet either

 

[kevplumb]

don't bank on it bonny lad

 

[bster]

have i still got a job?