Author Topic: Central AC unit noise  (Read 3182 times)

Offline yogi4three

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Central AC unit noise
« on: June 23, 2011, 01:17:50 AM »
Hello All,

My central air conditioning unit started making a crackling type noise recently. At first I assumed it was condensate water dripping on metal or trickling through the piping (similar sound), but when I checked out the ceiling space the AC unit's located in, there was barely any condensate (I live in a relatively dry climate).  It almost sounds as if the crackling is coming from the refrigerant line.  This sound is made regardless of whether the blower is turned on. Any suggestions as to what could be making that noise, and whether a refrigerant line could produce a crackling sound?  It sounds like a crackling fire or rain on a tin roof, but there's no sign of dripping anywhere. I've attached an audio file of the noise.

Thanks in advance.

Offline Admin

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Re: Central AC unit noise
« Reply #1 on: June 23, 2011, 12:21:36 PM »
If your blower is off then the ac is off.  If you're hearing the noise when the system is off it probably has nothing to do with the Hvac system.  Could it be an animal running around?  I have to get home before I can listen to your audio clip. 

Offline yogi4three

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Re: Central AC unit noise
« Reply #2 on: June 23, 2011, 07:22:35 PM »
It's a central a/c unit in my condo.  It works as follows:

"The central chiller is ready for start up and operation after May 15th and only operates after this date when the outside temperature is above 15ºC in the shade.  When this temperature is reached the chiller and pumps automatically start up and circulate chilled water through the cooling coils in the bathroom ceiling of each condominium.  This chilled water circulating through the coils however doesn’t cool the condo, it requires that the fan for the unit be turned on to push air past these coils and out through the duct openings in the living room and bedroom(s) of the condo"

So even while the blower is off, I still have chilled water provided by my condo building running through the piping of my a/c unit. The sound seems to be coming from these pipes.

My building manager suggested "there may be air in the line and  you may need to get a plumber in to bleed the lines."