i have a 20/80 boiler and the pressure drops after a few days there is no leaks from the rads or manifolds all i do is top up the system and no problem but where is the water going its also dry at the over flow valve going out the appartment

Alex, November 2010

There must be a leak some where. Is there any pipework you cant see that might be leaking? Also is the overflow pipe deffinately always dry? It doesnt take too much lost water to drop the pressure. What happens when the heating is on, does the pressure go up above 3? If it does water will pass through the overflow. If this is happening it is a problem with the expansion vessel, it either needs recharging or replacing.

Garu Farhall, November 2010