My Lennox HVAC system started working intermittently as of a couple of months ago and over that period progressively worsened. It just wouldn't blow air. I determined that the issue was not with the compressor but the actual blower motor. The thermostat (Nest) reports that everything works fine, the compressor outside is blowing but the blower motor is not working. That causes the coils indoors to frost as the blower is not blowing to dissipate it.
The way I tested was using the two connectors to the motor, high and low voltage. They are both fine and the manual says if that is the case, that means the motor is dead. The manual suggests to replace the motor.
I have not taken the motor out yet but I am curious, as this unit is only about 5 years old, what causes a motor to go bad? And can it be fixed, since I am not sure if mine is still covered under the warranty? It's a single speed motor and the model number of the handler is CBX27UH. I have been researching online and some posts indicate it may be due to a bad capacitor but I don't think mine uses a capacitor unless it is inside the motor itself.
Best Answer
HVAC blower motors, which are almost always of the INDUCTION motor type, fail for a variety of reasons. I'll list what are common reasons:
As noted in the comments, these often have a starter circuit with a capacitor which can fail. This generally leaves the motor operational but it cannot be started.
Usually the first thing to check is the starter circuit and capacitor.