Main AC won't start

Rene T

Senior Member
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Joined
May 20, 2011
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23,151
Location
Farmington NH
I noticed a couple of days ago the AC had difficulty started but it did eventually start. Today I went to start it and I could here it sort of clicking a couple of times then it was quiet. I'm able to turn on the fan. I switched it to cool and tried again and the same thing happened. It clicked a couple of times like it wanted to start but then it was quiet.
I've heard may times here on the forum they talk about start capacitors. I'm not a electrician so this will be new to me. It is a Dometic AC and it's 7 years old.
I'm going to go on the roof and remove the shroud. What should I be looking for?
 
Most of these units are not meant to be serviced. You can grab a meter and check the capacitors (small metal cans usually next to the motor), but other than that, you should call an HVAC tech and ask them. The refrigerant is usually in a sealed system without a valve, so for them to check the pressures, they may need some special tools.
 
Fixed it.  My neighbor, who's a retired electrician, came over with his meter and did a bunch of checking. It appeared that I wasn't getting any 110 volts to the capacitor. Went into the RV and checked power at the circuit breaker. All was Sat. Checked power at the AC in the junction box and all was Sat. He then said it appears the thermostat wasn't sending a signal to the AC.  BINGO. The light went on. I had forgotten that I had the same issue last year and after me doing some trouble shooting, I also thought it had something to do with the thermostat.
What I did last year was cycle the lever for the temperature up and down several times and the AC went on. I just did the same thing just now and it started.  It appears that while the AC sat idle for several months, corrosion must have built up do to humidity stopping the power from getting through. All is good now.
 
I assume you are replacing the thermostat?

Also, a little dielectric grease does wonders in harsh climates.
 
cerd said:
I assume you are replacing the thermostat?

Also, a little dielectric grease does wonders in harsh climates.

I may have spoken too soon. I went to take the cover off to see how it's wiring for another member and the AC shut off while I was doing that. Then it would click and I could hear a low hum coming from the bottom of the AC. I may have to order a new T-Stat
 
Rene T said:
I may have spoken too soon. I went to take the cover off to see how it's wiring for another member and the AC shut off while I was doing that. Then it would click and I could hear a low hum coming from the bottom of the AC. I may have to order a new T-Stat

Install a new Honeywell digital. $24.00 at home depot and lowes. Put one in my 2002 wildcat this summer. Love it. 2 degree swing. You'll need to check youtube for installing. Inbox install direction won't work.
 

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