Home AC unit blower question

[82angelfan]

30 years electrician but not a ton actual motor knowledge. My blower on my roof top AC stopped blowing. Compressor is working, and when I started by hand (screwdriver) the blower it stayed running but medium speed and weak. What are the chances this is a capacitor issue or is it the actual motor. Heat wave hitting high desert this week.

 

[Sea Nile]

You may need a new capacitor. Exact same thing happened to my AC last month. New capacitor fixed it.

Your symptoms are Exactly what mine were

 

[82angelfan]

You may need a new capacitor. Exact same thing happened to my AC last month. New capacitor fixed it.

Your symptoms are Exactly what mine were

Thanks, buying CAP for $10 bucks. Motor is $120 if CAP doesn't fix it.

 

[Sea Nile]

Thanks, buying CAP for $10 bucks. Motor is $120 if CAP doesn't fix it.

You can test the cap with a multimeter before buying another. It's not a very good test, but it's better than nothing. If you use continuity setting, you may see the display flash some numbers for a quick second before going to NC. That's good. If the display is unresponsive or you actually have steady continuity, that's bad.

 

[mtnelect]

When summer comes around, the most common problem is the combination (Compressor and Fan) capacitor. For our Maintenance Contract customers, we automatically replace them every two years. Go to our website MountainElectricCompany.com.

 

[Jraef]

That symptom is often the centrifugal switch inside the motor that puts the starting cap into the circuit when stopped, the takes it out after the motor gets to 80% speed. Over time the switch gets gummed up with dust and oil, so it sticks open and the cap is not in the circuit next time you want to start. By starting it turning by hand, you get it going, but with not enough torque to fully accelerate.

The centrifugal switch is usually in the NDE (Non-Drive End) of the motor housing. They are simple to replace if you have even rudimentary mechanical skills. But sometimes all they need is a short of contact cleaner to get the gunk out (never squirt it in when energized though).