Help. I have a ravenheat rsf rs 100et, i thought it had developed a faulty air pressure switch, no ignition / no fan / no heat ! i checked the flue & rubber tubes, no problems, so replaced the pressure switch & still nothing. i tried to prove [ to myself ] it wasnt the pressure switch by bypassing it & hot wiring the connections [ to cut out the pressure switch ] & hey presto it works. I checked the original switch & its not faulty & presumablly neither is the new one. So no blockages, no fauly pressure switch & boiler works without pressure swich in place ! Any ideas anyone ??