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Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: 18360 on September 09, 2022, 08:47:32 pm

Title: Dometic AC Motor
Post by: 18360 on September 09, 2022, 08:47:32 pm
     My back AC unit has worked well these last 3 years.  Down here in Florida it has been running quite a bit.  All of a sudden it wasn't blowing like it usually does.  When I got close to the vent, I could feel the cold air, but it wasn't blowing.  It was making a normal noise but no blowing.  So, I went up top while my wife turned it on.  The motor made a humming sound, and I could feel it vibrating but didn't turn. The compressor appeared to be working.
    I don't know enough about this to proceed. Should I replace the motor or call a technician or just replace the whole unit.  It's the original unit.  I believe the older ones are built better and last longer than the newer ones.



Title: Re: Dometic AC Motor
Post by: folivier on September 09, 2022, 09:16:44 pm
First step is I'd change out the capacitors, cheap and much easier than changing the motor (which may not be available).
Title: Re: Dometic AC Motor
Post by: craneman on September 09, 2022, 09:38:22 pm
The condenser fan motors are available, as I have a new one in the shop I bought from Johnstone Supply last year. They are generic double shaft motors. I will look in the shop tomorrow and get numbers off it. Change the capacitor first to see if it fixes it.
Title: Re: Dometic AC Motor
Post by: Jan & Richard on September 09, 2022, 10:08:00 pm
    I don't know enough about this to proceed. Should I replace the motor or call a technician or just replace the whole unit. 
Hello Rick,

When you were up top did you remove the plastic shroud?  If you did, you are 2/3 of the way to fixing it yourself.  This can be very satisfying. 

As Forest said, it is almost certainly the capacitors that have gone bad.  The way to confirm this is when you are up top and you have your wife turn the A/C on and the motor is buzzing, give the squirrel cage fan a little push and if it then begins to run on it's own, you have identified that that the problem is the capacitors. 

There are likely two can shaped capacitors with two to four wires connected to each.  Take a picture before you remove them then take them out and take them to any plumbing/air conditioning supply house and they can sell you new ones.  The volts and micro farads (u/f)  numbers on the old and new capacitors don't have to be exactly the same but should be in the same range.  And you might as well replace both at the same time.  The two capacitors will cost a fraction of what a service call would be. 

I have had to replace the capacitors on both of my air conditioners at different times.  The first one was easy and the second one was a piece of cake. 

Good luck,

Richard
Title: Re: Dometic AC Motor
Post by: 18360 on September 09, 2022, 10:23:44 pm
Thanks.  We will do that.
Title: Re: Dometic AC Motor
Post by: craneman on September 10, 2022, 11:45:25 am
This is the motor for the Dometic Penguin. The capacitor was for both the compressor and the fan motor.

Title: Re: Dometic AC Motor
Post by: Barry & Cindy on September 10, 2022, 12:38:12 pm
We used a Zoom oiler to lub both ends of blower motor. Try to rotate the motor shaft to get oil into the bearing. Capacitors should also be replaced, often ahead of problems.
Title: Re: Dometic AC Motor
Post by: wolfe10 on September 10, 2022, 12:56:58 pm
And, many small containers of sewing machine oil have enough of a spout to get where you need to lube.

Of course, you can always dip the end of a clean screwdriver in the oil and use it to transfer the oil.  That is how I do it when lubing the furnace fan motor.
Title: Re: Dometic AC Motor
Post by: 18360 on September 12, 2022, 10:00:04 am
     The cage did start spinning and I'm getting cold air.  So do I loosen all of the little bolts on the inner shroud and is that where the capacitors are?
Title: Re: Dometic AC Motor
Post by: 18360 on September 12, 2022, 11:20:37 am
I turn off the breaker, pulled the side panel and took pictures and pulled the wires.  Now I'm going to try to find the capacitors locally.
Title: Re: Dometic AC Motor
Post by: juicesqueezer on September 12, 2022, 01:13:18 pm
I turn off the breaker, pulled the side panel and took pictures and pulled the wires.  Now I'm going to try to find the capacitors locally.


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