[noltian]

It started two weeks ago at night I heard the sudden buzzing sound from outside and got scared and turned off outside unit. The noise went away. After 10 to 15 minutes I turned it back on and I haven't heard this noise for two weeks.

Tonight, it did again. Instead of turning off, I went out to see. It seemed the air from condensor is not hot. I guess it means a/c is not running (?). I turned off again and the noise went away. obviously fan is running.

It's long holiday and I want to know if that's something I need to be really worried. I didn't get a tune up this year since my indoor coil was replace in Sepetember and didn't think I needed a tune up.

Is it somehing I should really worry and compressor going bad?
what's the really symptoms of a compressor going bad. I noticed my next a/c is making a simliar noise tonight but less noisy. I didn't dare to go to my next door's and check it out.

It's 3 ton split unit in Dallas, Texas. it's bryant and 10 years old. It was just the coil replaced last year. Condensor is 10 years old.

 

[Rcb2875]

Sounds like your compressor is locking up.

If they will also chatter when low on refrigerant, etc but not buzz. The buzzing is a locked rotor or voltage issues.

 

[shhvac14]

If the air coming from the condenser is not hot or warm you may be hearing the compressor trying to start but it will stop after only a few seconds as the overload opens and shuts it down. The compressor could be bad or there may be something keeping it from starting properly. This is not good and you should leave it off until someone can come out to look at it to prevent possible further damage. The other possibility is you are hearing one of the components inside the electrical compartment buzzing. This one is not so bad but can still cause more problems if not addressed soon. Can't really go into much more detail about this as it involves high-voltage parts and the rules forbid DIY instructions. Someone may read this post and think "that's what wrong with my system" and attempt to fix it themselves. Either way it is something that I would recommend having looked at soon unless the weather is mild enough for you to go without the A/C for a few days.

 

[snowbertca]

Check for ants getting into unit, can cause this; no joke. Call a reputable company to repair. Can't discuss diy here

 

[noltian]

If the air coming from the condenser is not hot or warm you may be hearing the compressor trying to start but it will stop after only a few seconds as the overload opens and shuts it down. The compressor could be bad or there may be something keeping it from starting properly. This is not good and you should leave it off until someone can come out to look at it to prevent possible further damage. The other possibility is you are hearing one of the components inside the electrical compartment buzzing. This one is not so bad but can still cause more problems if not addressed soon. Can't really go into much more detail about this as it involves high-voltage parts and the rules forbid DIY instructions. Someone may read this post and think "that's what wrong with my system" and attempt to fix it themselves. Either way it is something that I would recommend having looked at soon unless the weather is mild enough for you to go without the A/C for a few days.

I will try to minimize the usage till I can have someone look a but it's Dallas, it's 100 degree and it's the one of hottest summer I ever had here. Fortunately, it's the unit for downstairs and it won't run as much as upstairs one.

I turned on and I don't get the sound any more. It's strange that this happened twice so far only at night and the condensor does not get any sun at all.

 

[rzmsauce]

yes get it looked at while its not to late

 

[Pianoplayer]

Very loud buzzing, then no A/C

Lennox XC14-030-230-01, Installed June 2008

Has been working fine, and had complete check and measurements less than a month ago (to keep the warranty valid).

After running without problem for the last 36 hours, it started with a really loud buzz this afternoon, which continued for about 5 minutes. Buzz sounded like 60 Hz type.

Then buzz stopped but outside and blower fans continued. However, not blowing cold. Turned it off, waited, turned it on again, just fans, no compressor.

I had mentioned to the tech that sometimes it buzzed louder than at other times, but he said compressors sound different from time to time, not to worry.

When the A/C came on with the loud buzz today, our computers shut down, and the microwave lost its settings.

Could the A/C problem have been caused by a power surge? The circuit breaker for the A/C did not trip, and I would think the A/C would be protected from power line surges.

You folks were very helpful with a humidity problem I had when this unit was first installed, so many thanks in advance if you have any comments.

 

[snowbertca]

Time to call in that warranty. Your compressor is fried and shutting down on its internal breaker instead of the house one.

 

[hvacvegas]

For those regular guests posting:

A "buzzing" sound, with a lack of cooling, does NOT prove a bad compressor, or damaged compressor.

It's proves a part is buzzing, and is the system isn't cooling.
Off hand I can think of another part that is an extremely inexpensive repair, compared to a compressor.

To the original poster:
Have a service tech come out to look. It's possible your doing damage to you equitment, costing you more in the long run.

To Pianoplayer:

You need to create your own thread, instead of hijacking someone elses.

 

[amd]

Something as simple as worn contactor can cause loud buzzing.

 

[2old2rock]

Pay no attention to anyone telling you over the internet what's wrong.
Shut it off and wait for professional service.

 

[snowbertca]

For the record as a Regular guest, I'm trying to help without DIY. If the power is making computers and microwave oven reset it suggests a serious drop in voltage and the house breaker is maybe too large to let go quickly enough. Since a contactor was mentioned, yes they buzz, especially when full of ants or burnt contacts. Won't mention the other inexpensive part(s) that might prevent the compressor from starting. I'm also suggesting he get a qualified technician out.

 

[Pianoplayer]

Buzzing gone

Thanks to everyone for your comments - really appreciated.

After the loud buzzing, the compressor shut itself down, although the outside fan and the furnace blower still responded to the thermostat. I did shut everything down and waited till the tech arrived the next day.

When he asked me to turn it back on, everything worked just fine - no unusual noise. The compressor seems to have reset itself.

The suspicion is that it was a momentary voltage _drop_ that occurred at the same time that the A/C tried to start up. Here in Southern Ontario voltage drops are fairly common, and the tech mentioned that other customers in a nearby community have had similar problems - no A/C and then, when the tech arrives, all is fine.

To try to be clear -- the compressor when working normally makes a slight buzzing noise which can be heard near the outside unit. It was this same noise that was amplified tremendously when the problem occurred, so strong that it could be heard as loud inside the house.

The tech then spent about 1.5 hrs checking every aspect of the system very carefully. He found it basically OK but added some refrigerant _very slowly_ while watching the gauges.

Although I had had the annual maintenance visit three weeks ago by the same firm, the new tech found that the condenser coil was quite dirty so he proceeded to clean it thoroughly. This was the most complete and careful going-over the system has ever had and I was quite impressed.

"D.Tm 20 F. Balanced charge achieving 10 degrees of subcooling. Hi=320 psi, Lo = 142 psi. Liquid line temp @ 91 F."

Because the Lennox warranty covers parts only, I expected a hefty bill for this visit and was happily surprised to be given an invoice marked "warranty" with no amount due.

Thanks again for your responses.