Originally posted by casturbo
Door switch?....yeah right, just bypass it.

Young service techs might not have the experience of arrivng to a service call to find the wiring harness burn't to a crisp becasue a homeowner chagned the filter but didn't get the door properly installed. The blower pulled the heat/flames out and cause some major problems, poor combustion, high levels of combustion by products entering into the home.

That is why on all new FAU using combustion for heat you will find an interlock saftey switch to prevent this.[/u]

It's a saftey device and nobody shuld even suggest that it gets by-passed. Get the model & brand of your furnace and provide it to who ever you call , arrange for a annual service and while their there they'll have the part to replace, shold be very expensive if pa[u]rt of a annual service.