i have a dependable ninety two furnace the blower does not come on it just hums?

Kill power to furnace. Remove furnace panel Try and spin the blower wheel by hand both back and forth. If it moves freely more than likely the motor itself is fine. The RUN capacitor has failed. The run capacitor is a mounted on the outside of the blower housing and is typically held in place by a bracket with 1 screw. There are two wires that go to it. Its is silver in color and maybe round or oval. There is information on the side of the capacitor that you would need in order to replace it. Match the MFD and Voltage IE 5MFD 370 Volts Note you can replace this yourself just MAKE SURE THE POWER is off on the furnace and you DO NOT touch the spade terminals on the old capacitor as even though its bad, there is stored voltage in there. You just remove the two wire, Plug the two wires back on the new one just like the old one was. Button things back up and you should be in business. Its less than a 20 dollar part. Call a service man and your looking at and easy 150-175 You will need to order this online as you can not buy form and HVAC supply house. However, you could look in your phone book for a place that deals in electric motor and they would have this and should sell you the part. The other place that would have this is Grainger. There are not brand specif, meaning if you had a Bryant furnace you have to go to Bryant. And capacitor will work so long as it meets the MFD rating and Voltage.... Show More

Turn it off, secure the power to it and then try to turn the fan by hand. It should turn easily. If it does not then you need a service person to replace the unit. If it does turn easily, then the motor is bad and it needs to have a professional do a service and replace the motor.... Show More

Probably needs a new capacitor. It could have bad bearings, though.... Show More

Some thing stuck in the fan ? bad motor ?... Show More