My American Standard furnace fan won't turn on. It will ignite, when it gets to the blowing stage it will turn off.
All breakers check out fine. Can't find any other on/off switch inside unit.
A burnt smell comes from vents, the same smell of when you first turn of the heater for the first time after summer, (not the first for this year). Was working fine before this.
What else can I do at home, or is it time for a tech?
Jim

There are several things that could cause this. Can you check to see if there is power getting to the motor. If there is then I would suspect a bad motor, if there is not power to the motor I would expect maybe a fan relay or a limit switch.

How old is it, and how long does the gas stay on? If the gas is going off only seconds after it comes on, it is the flame detector. All furnaces will shut the gas off when a limit switch opens, if the blower doesn't come on. A newer furnace uses a timed delay, and the older ones a lower limit switch. Do you have a fan on position? If so, try starting the furnace with the fan on. Often they use a different relay and a higher speed winding for fan on and cooling. Check some of the other threads and post back with more details. Quite often these things are something a homeowner can fix themselves.

To do simple checks like this you do need some tools. A test light, a meter, or a voltage detector might be the best place to start with. I came across the niftiest gadget for trouble shooting, a voltage detector. They work through the insulation of wires. There are several brands. I have a GB Instruments GVD-505A, less than $15 at Home Depot. Touch it to a hot wire, and the end glows red. Find the doodad that lights it on one side, and not the other, and you have the culprit. You do not have to open up housings and expose electrical contacts. You are looking at where your hand is, not where the meter is. Most people are capable of doing repairs and will get it going and not get hurt if they use a little sense. The voltage detector makes it even easier.

Check the thermo limit temp switch for the bonnet air.

Check the thermo limit temp switch for the bonnet air.


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