Baxi Cmbi Boiler 105e?

if it rises when using your heating, its expansion vessel.

vessel has either lost its air charge or has split and air section is now full of water giving no free room for expansion.

vessel on back of boiler has tyre type valve, remove cap push pin in briefly:

if you get.....
air: maybe needs a bit more charge
nothing: needs charged
water: f*ck*d

iain
October 2008