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-   -   Air Conditioner - Just A Humming Sound (http://www.diychatroom.com/f17/air-conditioner-just-humming-sound-72801/)

Blauvster 06-04-2010 11:29 AM

Air Conditioner - Just A Humming Sound
 
Hello Everyone,

I got a call from my wife that the house was 87 F last night :eek:!

We have a split system Air Conditioner.

Seems the AC unit outside isn't turning on. All that comes from it is a small humming sound. Seems to be coming from the compressor. Is that what a compressor sounds like when it is running and the fan is not?

I thought maybe the starting cap went bad, so I tested it.
Compressor Cap - 35.8uF
Fan Cap - 3.25uF

Using the model info, I found a parts list. Says it has a 40+5MFD, I'm assuming that is just saying there are 2 caps in one package, a 40uF and 5uF. So is 36uF and 3.3uF close enough?

The contactor or relay is kicking on when I turn the unit on, and there is nothing else really in the system.

I can spin the fan with a screwdriver but it doesn't stay spinning.

Any ideas? Thanks in advance!

Blauvster 06-04-2010 12:09 PM

So wow! All my troubles were caused by a bug deciding to make a nice insulator in the contactor/relay.

I was checking voltages with the power on, and realized there was no continuity between the 240VAC in and the other side of the relay. All I initially checked was that the relay closed. Apparently a bug decided it would make a home between the contacts when it was off and when it came on realized it was a bad decision. Surprisingly to me is the resistance of a bug. It was measuring as an open circuit!

All the humming was coming from the relay.

yuri 06-04-2010 07:50 PM

Yep. We even have a flat rate price in our manual for removing "earwig bugs". Birds going down chimneys are another favorite. Nature can be expensive.:thumbsup:

beenthere 06-04-2010 08:24 PM

Quote:

Originally Posted by yuri (Post 451269)
Yep. We even have a flat rate price in our manual for removing "earwig bugs". Birds going down chimneys are another favorite. Nature can be expensive.:thumbsup:


Yep, make some money every year from ear wigs, and birds.


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