Potterton 28 - keeps losing pressure, rads need bleeding

[elmojo]

Hi,
We have got a Potterton 28 combi boiler and we keep losing pressure. When it's down to about 0.5 we re-fill it up to about 2. It takes between 5-7 days to go back down to 0.5 again. We had a gas man out (at a cost!) and he could see no sign of a leak from either the boiler itself or the pipe outside. There are no water marks on the ceiling from upstairs, and do damp carpets downstairs (have to mention that the downstairs floor is a suspended wooden one - so maybe water could drip down instead of making carpet wet). The radiators downstairs also seem to need fairly regular bleeding - every month or so. Would the rads needing bleeding explain our lack of water leaking evidence? Our pipes downstairs are under the floor and are behind some skirting board, so don't really want to rip up the floor just yet.

Can you get something for leaks in the system - or are we leaking too much for that?

We were just wondering if there are any other tests we could ask people to do that wouldn't involve too much disprution to the downstairs decoration.

Any advise at all would be very welcome.

Thanks
John

 

[Rob]

There is a leak sealing chemical which you put into the system, works well on small leaks. Have you checked every rad valve thoroughly, under the caps etc

 

[gas4you]

Could be the expansion vessel

 

[baxpoti]

Leave the pressure at 0.5 - 1 bar. Check to see if pressure still drops.

2 bar cold is too high.