Failed motor capacitor on furnace blower?

Old 03-31-11, 12:03 PM
Thread Starter
Join Date: Apr 2010
Location: USA
Posts: 9
Upvotes: 0
Received 0 Upvotes on 0 Posts
Failed motor capacitor on furnace blower?

Hello forum,

I have an oil burning forced air furnace to heat my home. Last night, the blower motor seemed to fail - it was stalled, humming loudly, and there was a distinct plasticy smell.

At first I assumed the motor itself was toast, but it turns freely by hand and once I'd shut the system down and let it cool for an hour or two, it started back up just fine.

I am suspecting that the motor's starter capacitor is shot, and I have a few questions. Firstly, based on these symptoms, does that sound accurate? Secondly, I see no obvious label or marking on the capacitor. How do I go about sizing the replacement? Is there some general range of acceptable values based on the motor's specs or do I need to really nail an exact replacement?
Old 03-31-11, 12:51 PM
hvactechfw's Avatar
Join Date: Jan 2011
Posts: 5,491
Upvotes: 0
Received 4 Upvotes on 4 Posts
1.) It may be the capacitor or the motor. just because the motor spins doesn't mean it is ok.
2.) may have to remove the blower assembly to look at the label on the motor which should list the cap size needed. You need to have the correct cap for the motor.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: