Same prob as Geoff Jan 09?.When the programmer calls,the boiler fan runs for 1sec,& does this for about 10/20mins without ignition,not even a spark. mine is getting longer between fan runs & ignition.If i break the air seal on the casing the fan runs continuously 5/10 mins & i can feal the air being pulled in,then ignition & continues normal running as per required when called for by the appropriate room/cylinder stats.As soon as it fires the first time i obviously re/seal the casing,WHICH IS ONLY OPEN SLIGHTLY,ie loosen retaining screws 2 turns,so retighten them.But when the programmer shuts the system down the prob starts over when the programmer calls for heat/water on the next cycle.Could this be the the micro/switch on the airflow pressure switch sticking,if so can the switch be changed on its own,or do i have to change the whole thing?

vince, February 2009

befour buying presure switch make sure the fan is cleaned and the tubes from fan to presure switch are clean if fan has brass conections clean with wire wool and make shure no white deposits

gaz, February 2009

sounds like a dodgy air pressure switch this can be changed on its own youll need GC number and Serial number to locate correct part.

STE, February 2009