Air Conditioning Hissing Noise - http://www.hvacmechanic.com/ Forums

Original message

bigbri033

99.141.248.31

"Air Conditioning Hissing Noise" , posted Sat 12 Jul 17:16

My air conditioning just started acting up a few days ago. It turns on and has run continuously without cooling the houseeven though cool air is blowing from the vents. I even turned the thermostat down to 60 and it reads that it is 83 in the house. Every once in a while I do hear a hissing noise from the vent, but it is not constant and just started two days ago. Last week when the thing actually worked and it turned off it made a few loud clicking noises, but still turned off, came on and worked normally.

I looked at the unit and the two lights indicate it should be working properly.

Replies:

Houston204

98.196.66.53

"Re(1):Air Conditioning Hissing Noise" , posted Sat 12 Jul 22:23

I usually associate a hissing noise with the outdoor fan motor not running when the compressor runs.

A capacitor can cause that.

Does the outdoor unit run?

"Tip of the Day" Remember to remove power first.

bigbri033

99.141.248.31

"Re(2):Air Conditioning Hissing Noise" , posted Sun 13 Jul 00:03

I went outside and the unit was not running.

Houston204

98.196.66.53

"Re(3):Air Conditioning Hissing Noise" , posted Sun 13 Jul 00:41

Probably a capacitor.
When the condenser fan motor does not run your compressor will bypass, causing a hissing noise. The compressor will eventually drop out on thermal protection leaving nothing running.

"Tip of the Day" Remember to remove power first.

bigbri033

99.141.248.31

"Re(4):Air Conditioning Hissing Noise" , posted Sun 13 Jul 08:28

Do you know a ballpark figure on how much that would be to replace? Is it something I can do myself?

Houston204

98.196.66.53

"Re(5):Air Conditioning Hissing Noise" , posted Sun 13 Jul 12:15

Dual capacitors cost more than standard caps (both shown above).

It would be about $160 to have a service tech out to replace a capacitor, if it is the problem. If the compressor is out on thermals when he gets there (because the stat was demanding cooling while the fan was not working) you can expect to pay another hours labor for him to cool down your compressor.
You can probably repair it yourself for under $50 if you have a meter.

All of this may be jumping the gun a bit though. We still must prove that you need a capacitor.
If you remove the panel and your capacitor is swollen on top, replace it. If is not swollen, you might need a meter.
Preferrably a meter that can measure caps...

"Tip of the Day" Remember to remove power first.

bigbri033

99.141.248.31

"Re(6):Air Conditioning Hissing Noise" , posted Sun 13 Jul 17:34

Think I found the problem. I opened the unit and the capacitor was not even attached. Looks like the wiring came off of it as it was just lying on the bottom of the unit and there is one red wire just lying there unattached to anything.

Don't see a spot to upload pictures or I would. This is a very old Fedders unit. Went to their website and can't find the model number. The model number is CFC030D3B.