HVAC Outside Unit Buzzing - Fan Running Intermittently

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Buzzed air conditioning is not a joke or a thrill. Call a pro. . Christopher A. Young Learn more about Jesus www.lds.org . .
The buzzing could be comming from a relay that controls the fan. It may be going bad.
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On Jun 11, 4:44 pm, shadow

Single phase motors are not self starting, they have an extra winding with a capacitor in series ans sometimes a centrifugal switch. It sounds like the start winding/circuit has some sort of intermittant connection. There is info here but you need some technical knowledge to understand it. http://en.wikipedia.org/wiki/Single-phase_induction_motor#Starting
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replying to harry , shadow wrote: Thanks for all the input. Sorry for starting a few arguments.
Our fan motor uses a dual run capacitor. It was all rusty with something that looked like it could have been a leak to one side. Could also have been just corrosion on the outside too - hard to say. The unit is at least 13 years old & we've owned the house for 8 years - it's probably all the original parts because we haven't had any problems with the outside unit until now. (Yes, I know we're due for an entire replacement - would like to make it until fall when the temperatures are more comfortable)
I agree that it could also be the fan motor - bought a new one just in case. Anything more than that, we'll wait for our HVAC friend to get back.
But I'm not ruling out the capacitor alone - on Friday, it was definitely just the fan not working because the return line was so hot. This morning, I don't think the compressor was running either because the line was room temp. To me, that would mean that either the capacitor didn't kick on the compressor or the compressor overheated & shut off. Again, I'm not a pro.
I was mostly curious about why pulling the disconnect was necessary to make things start working again. The fuses are old - I bet they're the originals - but they look OK. None of the copper on either the fuses or the connections looks corroded or anything.
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replying to shadow, shadow wrote: Sorry for the somewhat double post - It took a really long time for my original response to show up.
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replying to harry , shadow wrote: Thanks for the input.
Our fan is wired to a dual run capacitor - I agree it could be the fan motor itself, so we bought one just in case. Never hurts to have spare parts laying around.
I've been reading about the relays & other things that it could be. Anything more complicated than the capacitor or fan motor probably means we'll wait for my husband's HVAC pro friend to get back in town.
The capacitor looked awful - rusted to the point you couldn't read the labeling. The unit is 13+ years old & we've owned the house for 8 years without needing to make any repairs. I'd bet it was the original part.
I know what the compressor sounds like when it's running - the buzz/hum was much louder & somewhat different from that. Sounded more like what happened when the capacitor went bad in our air handler.
As for corrosion in the fuses, the fuses & the relay hardware looks nice, clean & shiny - although the fuses look pretty old. Our HVAC store didn't sell those, so we'll buy somewhere else or order.
We probably just need to replace the entire thing since the outdoor unit is over 13 years old and the inside unit is about 25 years old, but it would be nice to do it in the fall when the temps are lower.
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On Tuesday, June 11, 2013 4:45:02 PM UTC-4, shadow wrote:

Glad it's working out for you. Hopefully that will take care of you for a while.
The buzz may have been from the fan motor since you are pretty sure it was different from the compressor. The fan motor will still be getting power e ven though the cap is bad. The dual cap is a common failing item on outsid e units and is easily the cheapest part to try. I would have held off on b uying the spare motor since they are so easy to get but to each his own. T he only other significant part outside is the contactor (big fat relay) but when it fails nothing will be running.
Most of the compressors do have internal thermal protection and if overheat ing for some reason will cycle on and off as that protect kicks in and then the unit cools down.
I you replace it this fall you will most likely be getting the new refriger ant. R410 or "puron" as one company calls it. It will run at a higher pre ssure. I think school is still out on new equipment service life.
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replying to jamesgang , shadow wrote:

I was wondering about the service life myself.
A friend has a fairly new home with a high dollar lennox system. He's had nothing but trouble & is already thinking about replacing it.
Seems like nothing lasts like it used to.
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On Tuesday, June 11, 2013 9:44:01 PM UTC-4, shadow wrote:

http://www.homeownershub.com/maintenance/hvac-outside-unit-buzzing-fan-running-intermittently-751726-.htm

Yep, I have three 1 1/2 ton r22 heat pumps. Two tranes and one goodman. Contrary to the ads the tranes have been more trouble than the goodman. And I have a nearly full can of r22. I'm hoping to keep them running as long as I can :-)
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Buzzed driving is Drunk driving !!!!
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Yeah, the fan hums intermittently. But, can you sing the secone verse of intermittentlly?
. Christopher A. Young Learn more about Jesus www.lds.org . .
Buzzed driving is Drunk driving !!!!
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