After messing around trying to replace a hot water tap, I notice that the oressure gauge on my Worcester Highflow 400 boiler has gone off the scale! I have tried to reduce the pressure by opening the drain plug, but it has not changed the pressure reading. I think there must be an air lock in the boiler. Is there a way to reduce the pressure?

Mark, October 2008

what your looking for is a prv in the boiler look to the manfactuers instructions for its position it should have a black lever that you can lift up to release the pressure

bob heating engineer, October 2008

have you turned the filling loop on accidently?,if so turn it off...then try draining a little of the pressure out,down to about 1.5 bar...

paul, October 2008