HVAC Outside Unit Buzzing - Fan Running Intermittently

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Hi,
I've been combing this site for information, but I have a question I can't find an answer for.
Here's our situation -
1. Last friday, we noticed the outside HVAC unit was making a loud humming/buzzing and the fan wasn't running.
2. We turned it off & on from the inside of the house with no change. Buzzing stops when outside unit is off, indoor unit blows fine, the thin copper line was burning hot at the inside unit (didn't check the outside).
3. Started looking here & saw the stick test. Fan moved freely with a stick, but we still didn't turn it back on for about an hour. In the meantime, my husband checked the fuses on the disconnect & called his HVAC buddy who seems to be on vacation.
4. When we put the fuses back in the disconnect & turned it back on, everything started up fine & it ran good until sometime last night (today is Tuesday). We had a ton of ran dumped on us last Friday from a tropical storm & were hoping maybe something got flooded or something & we could make it until my husband's friend is available.
5. So, today we left it off for about an hour, tried it & it still buzzed. Fan turns freely with a push. My husband went out to take off the access panel to pull the capacitor (all rusted up) to get a replacement & decided to pull the fuse & put it back on one more time just to see. Starts up like a charm.
He's going to get a new capacitor, new fuses & a new motor (just in case because with our luck it would run again until next friday night & go out for good in 100 degree heat) - but I can't understand why pulling those fuses & putting them back in does anything. Is it just coincidence that we finally let everything cool off enough?
The outside unit is probably close to 15 years old & the inside unit is the original with the house (from 1988) so we're due for a whole new setup, but I'd like to make it through the summer & have the replacement done in the spring or fall when the outdoor temps are more bearable.
Thanks in advance for your help
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Where exactly in the unit is the buzzing coming from?
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replying to recyclebinned , shadow wrote:

I'm not sure - it sounds like the whole thing is buzzing & we didn't want to power it up with the access panels off. That's a lot of electricity coming through there.
However, we've had problems with the inside motor doing the same thing - bad capacitor or motor seized - and it makes about the same sound.
We just switched out the capacitor & turned it back on - big copper pipe at the air handler already has condensation on it, small pipe is about room temp.
Only problem is that we have no idea if it's fixed or not since pulling the quick disconnect outside & reinserting it seems to reset something. Any ideas on that? It doesn't make any sense to me.
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On Jun 11, 1:44 pm, shadow

OMG, run and hide under the bed!! If running an AC with the cover off is so frightning, time to call a pro.
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On 6/11/2013 1:44 PM, shadow wrote:

I am about to have a similar problem. Where can I buy the capacitor?
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Ebay, Amazon. Usual places. . Christopher A. Young Learn more about Jesus www.lds.org . .
I am about to have a similar problem. Where can I buy the capacitor?
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Remember. It's not a joke, or a dare or a thrill Buzzed air conditioning is broken air conditioning. Call a pro before you get busted. . Christopher A. Young Learn more about Jesus www.lds.org . .
Where exactly in the unit is the buzzing coming from?
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On Tuesday, June 11, 2013 11:44:03 AM UTC-4, shadow wrote:

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It maybe that there was corrosion buildup in the fuse or disconnect that yo ur husband "fixed" by removing and re-inserting it.
There are two major active components in the outside unit, a compressor and a fan. The compressor raises the refrigerant pressure which also concentr ates the heat. The refrigerant then gets circulated through the finned tub ing where the air from the fan cools it.
From your description it sounds like the compressor was running and the fan was not. The "buzzing" was probably the compressor. The fact that the sm all tube coming out of the unit was very hot also indicates that the compre ssor was running.
The compressor and fan are usually both turned on by on big relay, aka a co ntactor. The compressor and fan also both have capacitors or sometimes the y share what looks like one capacitor that really has two inside it.
I don't generally recommend troubleshooting by replacing parts but if you a re going to do that, the capacitor is the most likely suspect part and is a lso not very expensive. So I would try that first. The fan motor will be a bit pricer so I'd hold off on that. Most places will not take back elect rical parts.
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your husband "fixed" by removing and re-inserting it.
No because from orignal post, only the fan was not running. There was "buzzing" and the pressure side line at the air hander was hot.

nd a fan.  The compressor raises the refrigerant pressure which also conc entrates the heat.  The refrigerant then gets circulated through the finn ed tubing where the air from the fan cools it.

an was not.
No shit sherlock, so why the diversion into corrosion at the dsconnect?
 The "buzzing" was probably the compressor.  The fact that the small tube coming out of the unit was very hot also indicates that the compressor was running.
See above.

contactor.  The compressor and fan also both have capacitors or sometimes they share what looks like one capacitor that really has two inside it.

are going to do that, the capacitor is the most likely suspect part and is also not very expensive.  So I would try that first.  The fan motor wi ll be a bit pricer so I'd hold off on that.  Most places will not take ba ck electrical parts.- Hide quoted text -

The capacitor? The freaking fan that is the most likely suspect doesn't have a cap. Good grief!
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ou are going to do that, the capacitor is the most likely suspect part and is also not very expensive.  So I would try that first.  The fan motor will be a bit pricer so I'd hold off on that.  Most places will not take back electrical parts.- Hide quoted text -

trader, you usually give out good info but in this case I'm not so sure...
the fan motor in my AC definitely does have a running cap so at least SOME units do have caps for the fan.. neither of us have any way of knowing specifically about the OPs unit...
OP, can you tell use the make and model number of your AC?
Mark
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you are going to do that, the capacitor is the most likely suspect part an d is also not very expensive.  So I would try that first.  The fan moto r will be a bit pricer so I'd hold off on that.  Most places will not tak e back electrical parts.- Hide quoted text -

I agree, many cooling fans in the outdoor compressor equipment box do use a capacitor.
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you are going to do that, the capacitor is the most likely suspect part an d is also not very expensive.  So I would try that first.  The fan moto r will be a bit pricer so I'd hold off on that.  Most places will not tak e back electrical parts.- Hide quoted text -

OK, got that wrong then. I thought only the compressor had a cap. So, could be either the cap, the motor, or some intermittent wiring problem.
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wrote:

if you are going to do that, the capacitor is the most likely suspect part and is also not very expensive.  So I would try that first.  The fan mo tor will be a bit pricer so I'd hold off on that.  Most places will not t ake back electrical parts.- Hide quoted text -

try oiling the fan motor if you can
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On Wednesday, June 12, 2013 2:21:00 PM UTC-4, bob haller wrote:

t if you are going to do that, the capacitor is the most likely suspect par t and is also not very expensive.  So I would try that first.  The fan motor will be a bit pricer so I'd hold off on that.  Most places will not take back electrical parts.- Hide quoted text -

f

Sadly practically none of them are oilable. While you can greatly extend t he life of a motor with periodic oiling less than 1% of the general populat ion is likely to do it on a regular basis.
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Not many people do maint on their equipment of any kind, at all. Maybe car oil change, but not much more than that. . Christopher A. Young Learn more about Jesus www.lds.org . .

Sadly practically none of them are oilable. While you can greatly extend the life of a motor with periodic oiling less than 1% of the general population is likely to do it on a regular basis.
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I didn't read this whole thread, but if you're hearing a buzzing noise, try tightening the screws on the outer panels of the unit.
Also, an iron core transformer is essentially an electromagnet that changes it's polarity 60 times per second, and the attraction to and repulsion from any nearby metal panels can cause both the transformer and panel to vibrate. So, tighten any mounting screws or bolts on transformers, too.
--
nestork


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On Tuesday, June 11, 2013 2:26:37 PM UTC-4, snipped-for-privacy@optonline.net wrote:

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t your husband "fixed" by removing and re-inserting it.

and a fan.  The compressor raises the refrigerant pressure which also co ncentrates the heat.  The refrigerant then gets circulated through the fi nned tubing where the air from the fan cools it.

fan was not.

a contactor.  The compressor and fan also both have capacitors or sometim es they share what looks like one capacitor that really has two inside it.

ou are going to do that, the capacitor is the most likely suspect part and is also not very expensive.  So I would try that first.  The fan motor will be a bit pricer so I'd hold off on that.  Most places will not take back electrical parts.- Hide quoted text -

I suggest you do your research a little more carefully. 99% of outdoor uni ts have a dual cap that is for both the fan and the compressor. It may be that you didn't realize the cap was really two caps but if you look at the wiring you will see differently.
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On Jun 11, 11:44 am, shadow

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Those symptoms all point to a bad fan motor.

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It sounds like coincidence. Sometimes with a failing motor, if you turn it, it may work again......for awhile. Forget about the capacitor. Even with the fan going, you reported that the pressure line was hot, so the buzzing must be the compressor. If the compressor was not running, you would not have a hot line. The cap is the starting cap for the compressor. The small motor for the fan, AFAIK, doesn't have a cap.
I would open it up enough so you can get a meter connected to the fan motor. If it has 240V and the fan ain't going, you've confirmed the problem.

From what I've heard so far, seems like you should be able to do that for the cost of a fan motor, which isn't that much.
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message

The buzzing could be comming from a relay that controls the fan. It may be going bad.
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wrote:

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But more likely, the "buzz" is the compressor running
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