I have a Saunier Duval Enviroplus F28e SB. Drained the rads yesteday, refilled the sytem. Ever since the rad circuit runs but when you turn on the hot water it releases steam from the pressure relief valve and does not run hot. Red light comes on and displays code F9 pressure sensor fault. Any ideas as to how the sensor may have been affected by doing this?

Also the fill loop is not functioning.

Simon, June 2009