My baxi solo wall mounted boiler is fitted with an expansion tank(red shaped tank with valve). Recently the overheat light has came on and on ckecking the pressure gauge found that the water had emtied.I refill the system,turn on the heating which works but the pressure continues to build and the overheat light comes on.I have bled the radiators when cold and hot and this appears to make the problem worse.Any advice please

alistair mcharg, October 2006

must ah been all that screwing ANGELA that did it lmao

billy, June 2010

This sounds like the red exspansion vessle requires re-charging.
Open the valve near the vessle (this will say 3Bar on it) to middle position any water left in the system will come drain outside, you will require a foot pump on the vessle you see a car wheel type valve remove the dust cap and pump the vessle to 1.0 Bar which slightly higher than needed but you will loose some pressure when removing it. close the PRV valve and fill the system as normal.

David, October 2006