From cold,
The fan is running ok , the pressure switch is ok ( new ) all pipes to air pressure switch are clear

Boiler begins start sequence , but stops just as fan runs , this happens for about 15/20 times then the boiler fires , then runs ok until shut down , and problem returns ant next switch on time ??

sparkey, January 2007

control board has done the trick

sparkey, February 2007

Hi, did one of these today. changed the air pressure switch, still the same problem (checked with meter and was faulty) then replaced pcb all fired up OK

Paul the gas man, January 2007