If you are looking for information on wiring a 3-speed furnace blower motor, you have come to the right place. Here, we will discuss the wiring diagram for a 3-speed furnace blower motor, along with some frequently asked questions.
Wiring Diagram
The wiring diagram for a 3-speed furnace blower motor can vary depending on the manufacturer and model of your furnace. However, the basic wiring diagram usually follows the same pattern:
| Wire Color | Function |
|---|---|
| Black | High Speed |
| Blue | Medium Speed |
| Red | Low Speed |
| White | Common |
As you can see, the black wire is for high speed, the blue wire is for medium speed, the red wire is for low speed, and the white wire is the common wire.
High Speed
The black wire is for high speed. This wire should be connected to the high speed terminal on the furnace control board or relay.
If your furnace does not have a high speed terminal, you can connect the black wire to a high speed wire nut or terminal block. Make sure to consult your furnace’s manual or seek professional help if you are unsure.
Medium Speed
The blue wire is for medium speed. This wire should be connected to the medium speed terminal on the furnace control board or relay.
If your furnace does not have a medium speed terminal, you can connect the blue wire to a medium speed wire nut or terminal block. Make sure to consult your furnace’s manual or seek professional help if you are unsure.
Low Speed
The red wire is for low speed. This wire should be connected to the low speed terminal on the furnace control board or relay.
If your furnace does not have a low speed terminal, you can connect the red wire to a low speed wire nut or terminal block. Make sure to consult your furnace’s manual or seek professional help if you are unsure.
Frequently Asked Questions
Can I wire a 3-speed furnace blower motor to a single-speed thermostat?
No. A single-speed thermostat is not designed to control a 3-speed furnace blower motor. You will need a thermostat that is specifically designed to control a variable-speed motor.
Can I wire a 3-speed furnace blower motor to a 2-speed thermostat?
Yes, but the thermostat will only be able to control two of the three speeds. You will need to connect the high and low speed wires to the thermostat and leave the medium speed wire unconnected.
Can I wire a 3-speed furnace blower motor to a speed controller?
Yes, but you will need a speed controller that is specifically designed for use with a furnace blower motor. Make sure to consult the manufacturer’s instructions and seek professional help if you are unsure.
Can I wire a 3-speed furnace blower motor to a timer or humidistat?
No. A timer or humidistat is not designed to control a furnace blower motor. You will need a thermostat that is specifically designed to control a variable-speed motor.
What if my furnace has a different color coding for the wires?
If your furnace has a different color coding for the wires, consult your furnace’s manual or seek professional help to identify which wire is which. Do not rely on the wire colors alone to determine which wire is which.
With this information, you should be able to wire a 3-speed furnace blower motor with ease. Make sure to consult your furnace’s manual or seek professional help if you are unsure about any part of the wiring process.
