ravenheat LS80T?

Ckeck the expansion vessel on rear of boiler, should be charged to approx 0.5 to 1 bar pressure (air) use a car tyre foot pump with gauge, you will need to do this with boiler drained and drain plug removed, or you will get false reading from xp vessel. If you get water out of tyre valve on xp vessel then it' s burst and it will require replacing. Also ensure the filling loop is disconnected after use this may cause over pressurizing if passing!

Belly
March 2008