The simple answer is that you need to refill your boiler with fresh water...this is done by the filling loop which is essentially a connection from your mains water supply into the boiler itself. Look for a flexible, braided water pipe with a tap on one end that enters your boiler. Alternatively if its a newish one, there may be a white plastic tap near the bottom of the boiler, beneath the main cover. Either way, introduce water into the boiler until the pressure is correct, but don't overdo it!
John, March 2009
