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alsk123 · Dec 23, 2007, 01:29 PM

Hi,

I have a rheem furnace in which the blower motor buzzes but does not run. I replaced the motor, and the capacitor(15/370 MFD) but the same problem persists. The motor that was initially on the system (51-18716-01) is no longer sold so I bought the one that replaces it ( 51-23017-42). The only difference between the two is that this new motor has two brown capacitor wires. When I attach both brown capacitor wires to the capacitor, the motor runs but it runs slow and it hums and after a minute turns off. If I attach only one of the brown capacitor wires coming from the motor to the capacitor the motor buzzes but does not run. If I then turn the blower with my hand, the blower runs fast at its normal speed.
Do the brown wires from the motor provide electricity from the motor to the capacitor, or from the capacitor to the motor? I checked the voltage on both wires when not attached to the capacitor, and one the voltage coming from one is about 158V and the other around 4V. I see the same voltage on the old capacitor.I see a Voltage of 4V on the white wire from the motor attached to the capacitor, and around 4V on the beige wire coming from the junction box that is attached to the capacitor.
What do you guys think is the problem?
Thank you very much in advance for your input.

Merry Christmas, and happy holidays.

hvac1000 · Dec 23, 2007, 05:05 PM

Did you buy a new Capacitor for the motor you are now using?
Could very well be a bad Capacitor.

alsk123 · Dec 23, 2007, 08:09 PM

Hi,

Thank you for the replies. I did buy a new capacitor, and a motor.
Here are the wires from the motor and how I have connected them:
Black,red, white, blue, yellow, brown, brown
What I have done is to connect the black from the motor to the black coming from the jbox, and the red from the motor to the red coming from the jbox. I also have the while from the motor connected to one side of the capacitor. On the same side of the capacitor, I have also connected the white coming from the jbox. On the other side of the capacitor I have connected the two brown wires, but as I have mentioned when I do that the motor hums and runs very slowly for about 30 seconds before shutting down. If I connect only one of their of the brown wires to the motor buzzes, and then if I turn the blower with my hand, it runs normal. The yellow and blue I have not connected to anything since it was also the same on the old motor.

Thanks again for your help.

hvac1000 · Dec 23, 2007, 10:00 PM

Without seeing the motor wiring diagram I am going to take a educated guess. I believe both brown wires go to the capacitor. One to each side of it.

The white goes to the common or neutral side or the motor power circuit and then the black,red.blue and yellow are the different speeds. I assume this is a 120 volt motor?

Give this a try. There is also some motor wiring help in the sticky notes at the beginning of this board.

alsk123 · Dec 24, 2007, 06:02 PM

Thank you very much for your help. The wiring you suggested works. I am surprised that it is not the same as the sticky on the motor.
Happy Holidays.

AC Doc · Dec 24, 2007, 07:01 PM

The key factors for replacing a motor are HP= Horsepower, RPM=Revolutions per minute, and voltage. The high voltage wires should be one to the incoming voltage and the other to a relay or sequencer (SWITCH). This switch could be bad and not passing a good connection. You can check it by jumping around it. The two brown wires get connected to the new capacitor only. You may have a two speed motor that gets high speed for heating and medium for cooling. Make sure the new capacitor is what the motor requires. It should be written on the label.

hvac1000 · Dec 24, 2007, 08:33 PM

Originally Posted by alsk123

Thank you very much for your help. The wiring you suggested works. I am surprised that it is not the same as the sticky on the motor.
Happy Holidays.

Sometimes the diagram on the motor can be confusing. Glad you got it going. Merry Christmas

limuobai · Mar 21, 2008, 08:32 PM

Originally Posted by alsk123

Hi,

I have a rheem furnace in which the blower motor buzzes but does not run. I replaced the motor, and the capacitor(15/370 MFD) but the same problem persists. The motor that was initially on the system (51-18716-01) is no longer sold so I bought the one that replaces it ( 51-23017-42). The only difference between the two is that this new motor has two brown capacitor wires. When I attach both brown capacitor wires to the capacitor, the motor runs but it runs slow and it hums and after a minute turns off. If I attach only one of the brown capacitor wires coming from the motor to the capacitor the motor buzzes but does not run. If I then turn the blower with my hand, the blower runs fast at its normal speed.
Do the brown wires from the motor provide electricity from the motor to the capacitor, or from the capacitor to the motor? I checked the voltage on both wires when not attached to the capacitor, and one the voltage coming from one is about 158V and the other around 4V. I see the same voltage on the old capacitor.I see a Voltage of 4V on the white wire from the motor attached to the capacitor, and around 4V on the beige wire coming from the junction box that is attached to the capacitor.
What do you guys think is the problem?
Thank you very much in advance for your input.

Merry Christmas, and happy holidays.

I have exactly the problem as you had. I don't understand HVAC1000's answer. Did you have to put 2 brown wires one on each terminal of the capacitor? I did that and tripped circuit breaker. Could you describe you wiring again?