Hi
Our Potterton Prima F 50 never switches off, but as my wife mistakenly turned off the gas, the boiler went off for once. We don't have the instructions, the thermostat handle is even missing, but the agency told us we would have to pay to reset it. The electrician told us to look on the internet for how to reset a Potterton Prima F 50 (kind from him). I followed the above intructions given by "b", and it did work and saved us £40.
Thanks!
Berty, May 2010