natev

My air handler blower motor started "stuttering" last week. It's keeping the house cool but it will start up fine blowing air & then randomly stop for a second and start up again and stop for a second - sometimes a few times in a row & sometimes it stops for a longer period but never more than a second or two before it gets going again. .
There's no pattern to it - it's completely random & there are no "bad sounds" or smells...

Is this most likely the motor or could it be the fan relay? How do I test that?

I opened the air handler & it's horizontally mounted (mount is on the left) & it almost looks like I have to remove the heat pump element & electrical connections to get the squirrel cage out if I need to replace the motor - is there an easy way to get it out or does it just look more complicated than it is?

I'd like to figure this out before it stops completely & we're stuck with no AC in 100+ degree weather.

Any help would be greatly appreciated. I believe it may be Lennox or Carrier (outside unit is a Lennox but the only tag I was able to find near the motor was the fan wheel which is a Carrier wheel)

kok328

If you have the capability, check the motor's capacitor. If not, it is a inexpensive first guess to fixing the problem.

natev

Could the behavior of the motor I described (stopping & starting randomly) be a symptom of the capacitor going bad?
The capacitor is not mushrooming or anything I can see visually, unfortunately I don't have a meter that can test ferads.

kok328

yes, this is sometimes a symptom. Perhaps, you could have it tested or just replace it for around $20 or less.

natev

So I went to Grainger this morning & picked up a replacement capacitor for $6. Took me 7 mins to replace it & it's been through 2 cycles now without messing up! Hopefully that was what it needed - thanks for the replies!

kok328

Successfully troubleshooting HVAC without seeing, hearing or touching isn't easy.
An educated guess at best.

Congratulations !!

natev

One more question - what's the difference between a cap that says 50/60 Hz & one that says 60/50 Hz?
The guy at Grainger said it didn't matter since the voltage (370 VAC) & microferads (7.5) were the same...
Just wondering if that would affect anything...

Also - I better check with you to see if on a single run capacitor (the one with just 2 terminals) does it matter which brown wire goes to which terminal? Ie...does the one with the white stripe need to be on a specific terminal & the one without the white stripe on the other - only 2 terminals & only 2 wires...wondering if it matters which is which)

Thanks!

kok328

No difference between 50/60 Hz & 60/50 Hz, it's just the order that the manufacturer decided to print it.
In the USA, we are 60Hz.
Wire and terminal connections do not matter on this particular cap.

natev

Thanks again! Just wanted to make sure I wasn't going to blow anything up

natev

Ok - worked great yesterday & now it's doing the same thing this afternoon...could I possibly have gotten a bad capacitor then?