The boiler fires up and runs ok for about a minute,before it starts to switch off and then reignite,this happening once every second.So there is a constant bumpf bumpf as the boiler reignites.The 4 neon lights on the pcb initially all light up until the problem starts,resulting in light 4 flashing on and off in unison with the relay on the pcb and the boiler igniting.I thought the problem might have been a faulty pcb relay or main solenoid fault.However,I removed the front cover and it worked pretty well normally with an occasional switch off.The vent pipe looking from the out side is clear.

peter, February 2008

I found the answer.The pilot jet was partially blocked.On this model it seems the pilot must stay alight even tho the main burners are on.Once the pilot was cleaned I put every thing back and it worked perfectly.The moral is,keep your boiler serviced.

peter, April 2008

I have exactly the same problem with the 120FF

Have you found a solution to the problem? I was about to buy a new PCB which I think is where the fault lies.

Daniel.Goodman@e-business.com

Daniel Goodman, March 2008