I was having problems with a furnace. It would come on for about 90 seconds and turn off. And no, the room definitely was not at all too warm already. Fortunately, I have people who know about such things and for the cost of nothing but a little time, it got fixed.
I took off the two furnace doors. There is a door switch on one of the doors that prevents the furnace from running when it is off. But I want it to run with the doors off. How else can I see what is going on? So I tape it down with some electrical tape because that is all I have at the moment.
To trick the furnace into turning on, I put a wire between terminals marked W(white wire) and R(red wire) which tells the furnace to bring the heat. I see the small induction fan turn on, the burners turn on, then the big blower fan turns on, and then it all shuts off.
There is a light blinking 3 red flashes on the controller board. There is a code cheat sheet on the back of one of the furnace doors. This tells me that 3 reds mean that the pressure switch is stuck open.
My experienced friend tells me there is a rubber hose between the induction motor and pressure switch and to remove the hose from the black switch side and blow into it with my mouth. No can do, it is plugged up.
Now he has me remove the other end of the hose and I can see that the metal port that the rubber tube connects to is full of white chalky stuff. I use a piece of wire to clean it out (it is ok if it falls inside. The induction fan blades are behind this port).
I put the hose back on and now the heater comes on and keeps on running just the way it should. This quick little fix saved me from having to call a repair guy and then wait in the cold for the said repair guy to show up. Plus, it probably saved me over $100.
An easy life is one full of good family and friends. It is extra nice when these wonderful people know stuff and you can help and support each other. Thanks, my friend!