When you have an electrical surge any component could have been damaged. You may have more than one problem and not realize it . It is hard to trouble shoot.

I would think that only one tap at a time can be engerized to 24 volts. This would set the desired motor speed for heating and cooling operation.

You can check the the G (fan) , W (heat), and Y (cool) terminals at the thermostat to see it is putting out 24 volts when calling for heating and cooling.

Is the air handler wired for 240V? If it is check that you are getting both phases of power. You may have lost one phase and the motor is only getting 120V which is causing it to run very slow and not able to start up.

I checked power at the integral motor controller, there was 240V between pins L & N, so the power is there. I guess the motor failed, I just was confused when the service literature stated there should be 24VAC on pins 1 through 5.

Reading the literature about the system it states that the motor is a constant torque and it's torque is maintained regardless of fan speed, I assumed this meant that there would be some combination of control voltages on the pins in question. I just wanted to eliminate other possible culprits before shelling out $500 for a new motor.

I found this installation document and I am trying to dipher how the taps work. I find it confusing.

After reading it multiple times, I believe the G wire should be connected to tap 1, and the Y wire is probably connect to tap 3. This is the typical factory set up. When you set the thermostat to fan the G terminal should have 24 volts. According to this document this is a continuous low speed fan operation. When you the thermostat calls for cooling, then the Y should engerize tap 3 which is set for 400 CFM air flow per ton per ton. Normally thermostats will energize the G and Y connections at the same time.

So you should see tap 1 energized by itself when the fan is on, and tap 3 energized when the AC is on.

I am not an expert in fixing Lennox air handlers so I don't want you to buy a $500 motor solely based on my diagnosis. I hope I am not steering you down the wrong path.

Good luck.

Here is a link that might be useful: CBX27UH Installation document

Mike,

I appreciate your input. I am trying to eliminate the possible culprits to minimize the chances of buying something I don't need. I traced the wires from the thermostat up to the air handler, they seem to go first to the condenser's controller before coming back to the air handler. I'll try to read the schematic to see if this is in fact the case. I hope it isn't as it adds one more variable to the mix ;-(

Guy

That was quick installation. How did you find the new motor so quickly. Was it difficult to install? What was the total cost of the repair?

First thing I did was search the Internet for anyone selling Lennox HVAC equipment, I found two that were extremely helpful: HVACPARTSSHOP.COM & ACFURNACEPARTS.COM

Both emailed the manufacturer's service literature for my system.
With that I was able to prove the motor was receiving everything it needed to run and since it didn't well it likely was at fault.

The motor was available from both of the above, the cost was $400.
However, I contacted the original system installer and found that it was still under warranty. They quoted $450 for labor to replace the warrantied motor!

I complained that it was absurd to charge so much for labor as I found it took less that 10 minutes to remove the blower cage and extract the motor myself. They wouldn't budge on price but told me of the Lennox distributor in my area. The distributor was able to check the warranty and did an over the counter exchange, FREE of any charge.

It truly was an incredibly easy repair. Once I decided to pull the plug on replacing the motor what took the longest time was the drive to the distributor, about an hour in heavy traffic each way.

That's great! You got an exact replacement motor for free and it sounds like the swap was relatively easy.

I am glad to hear this worked out well for you.

I have a 5 year old Lennox CBX27UH my blower fan is running very slowly. How can I determine if my blower fan motor is bad or not getting enough power to make it run properly?

i would gladly accept calls also to Jim at 517 285-3112

Not a good idea to put personal information on a public forum. I believe your air handler has the X-13 motor, which doesn't have a control module. Likely the motor is bad. If you registered the unit when it was installed, you should have a 10 year parts warranty.