To buy a new furnace blower motor the old blower motor face plate will need to be looked at. The tag on the motor will say what horsepower it is, the RPM, Voltage, and amps.
The model number can be used but in many cases old model numbers don’t match up to new ones. If you cannot find exact model number replacement then a universal replacement motor that matches the HP, RPM, Amp, Voltage, Speed along with shaft size will need to be bought.
If you can find a exact model number replacement then you are done you will simply need to order it.
If you can’t find an exact model number replacement then an equal replacement will have to be found. Motor manufactures make universal blower motors that can be wired to run at a wide range of settings depending how they are wired.
For example, you have a 1/2 HP blower motor and can’t find an exact model replacement you can buy a universal motor that runs at 1/4 HP,1/3, 1/2 HP depending on which wires from the motor are used.
Write down the following information from the tag on the motor when looking for a blower motor, then find one that matches your motor for a replacement.
Details Needed to Buy a Furnace Blower Motor
- RPM: If the motor has multiple speeds then only the highest speed will be listed. Common motor speeds are 1200, 1075, and so on.
- HP: 1/8, 1/3, 1/4, or 1/2
- Amp: 5 uf, 6 uf, and so on
- Voltage: 120 Volts or 240 Volts
- Speed: 1 speed, 2 speed, or 3 speed
- Shaft size: Most furnace motors use a 1/2 inch but sometimes they can be different.
Here is an example of a furnace blower motor on Amazon. You can see the listing description the specifications are listed for the motor.
Example Furnace Blower Motor On Amazon
A.O. Smith/Century DL1056 1/2 HP, 1075 RPM, 3 Speed, 115 Volts6.5 Amps, 48 Frame, Sleeve Bearing Direct Drive Blower Motor
Some furnaces don’t use a capacitor while others will have both a START and RUN capacitor. But most furnaces by far have a single capacitor.
Capacitors are measured in voltage and uf (micro farads). To find a replacement look at the capacitor and write down the Voltage (120, 240, 370, 440) and the uf (4-10 amps) and then order a replacement.
Here is an example capacitor that is 370 volts 5 uf.
Any capacitor that is 370 volts 5 uf can replace this capacitor. The same will apply to any other capacitor simply match the voltage and micro farads.
(The part that says +-5% is what the capacitor is rated to go up or down from.)
Any capacitor that matches yours in voltage and amps will work.
Here is an example on Amazon, as you can see in the listing description it shows the uf and voltage.
Example Furnace Capacitor On Amazon
OneTrip Parts USA Capacitor 5 MFD – 5 uF 370 VAC Oval Replacement For Rheem Ruud Weatherking 43-25134-02
Where to Buy Parts
I like to buy my parts from Amazon and sometimes eBay, the parts are much cheaper compared to a HVAC supply store. If you are in a hurry then you can buy the parts at a HVAC supply store. Some don’t like to work with non HVAC people because of damaged parts being returned while others will not care. If you can wait a few days for parts to be delivered then I would suggest Amazon.