AC Puzzled - Printable Version

AC Puzzled - Printable Version

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RE: AC Puzzled - Brad Townsend - 07-05-2016

Ok Jon
I will try that when I get to working on it.

RE: AC Puzzled - Brad Townsend - 07-16-2016

Well I finally got a chance to work on the AC unit with no positive results.
Looked for any of the controls to loose power that would shut down the fan and nothing.

Only thing I did notice, on the blower relay with a meter just prior to the fan quitting I could see the voltage go down which ultimately causes the amperage to go up which resulted in the compressor to overheat and then the breaker popped.
So could this be a bad relay or would there be something else causing the voltage to lower thus seeing it on the relay.

Tried to separate the fan from the compressor and both wires are connected to the same contact so can't do that.
I did go outside and under the coach and looked up under to the fan motor with flashlight and infrared temp gun.
The fan motor would reach 150 degrees before it would quit, sometimes 130 degrees. This was measured where the bearing should be. I also noticed that the air drier which was also replaced got frosted up then melted reaching a temp of around 90 degrees. My next attempt is to pull the unit out and separate the wire that controls the compressor to see if the fan continues to run.
Remember that in a prior note that while at newell they put an amp meter on the fan wire and it never jumped up in amperage prior to shutting down as if someone just flipped a switch.

I could be overlooking something in the box by the condenser, there is a lot of stuff going on in there but spent a lot of time trying to make sense of it.
This was not a problem prior to newell changing out the compressor and air drier, not to put blame on anyone just adding some facts so as to help solve the problem.

Brad

RE: AC Puzzled - Richard - 07-17-2016

Only thing I did notice, on the blower relay with a meter just prior to the fan quitting I could see the voltage go down which ultimately causes the amperage to go up which resulted in the compressor to overheat and then the breaker popped.

You could hot wire around the relay to see if that is the problem.

Also, and I feel like I have beat this point to death on the forums, please check all the wire connections supplying power to the unit. I found four different occasions (all three units on 390, and one unit on 512) that the wire nuts had vibrated loose just a bit and the connection was not tight resulting in burned wiring.

I have converted to this connection for my AC compressor wiring to circumvent the problem. https://www.amazon.com/King-Innovation-95125-AlumiConn/dp/B003ZFUHOG Some Lowe's stores also carry them.

RE: AC Puzzled - 77newell - 07-17-2016

Another possible way to fix the wire nuts in place is to put shrink tubing over them once they are tight, or wrap them with tape. Wire nuts aren't designed for vibrating environments so they need a little help from their friends (us).

RE: AC Puzzled - Guy - 07-17-2016

Just curious, did Newell use wire nuts in coach building? I have found them in my coach but thought they came from previous owners..

Being in the electrical business, I had some Ideal 2006S crimps, and covered them with a 2007 Ideal insulators. About 15 cents per termination. Add in a 30 dollar crimper, T&B WT111M. Advantage, no set screw to come loose, Disadvantage, you have to cut them out, and loose a couple inches of wire ii you ever need to remove them. Ithink Amazon sells complete kits.

https://www.amazon.com/Ideal-2007-Splice-Connector-Pack/dp/B007EWYVZM

RE: AC Puzzled - Brad Townsend - 07-17-2016

On the blower relay I see 2 black wires a blue and a small red. Would one assume that I could put the 2 black wires together to by pass the relay? Looks like the blue goes to the thermostat wire. Small red wire may go to the transformer.

RE: AC Puzzled - Richard - 07-17-2016

Easy to confirm your guess. One wire should be HOT, when relay is off. Both wires should be HOT with relay on.

RE: AC Puzzled - Brad Townsend - 07-22-2016

Ok so I jumped the wires and it was the blower inside the coach not the condenser.
In checking the running temp on the other two blower motors, they run at 117 degrees each and the one in question pops at from 135 to 155. and the shaft is wet with what I imagine to be lubricant. So I am leaning to the blower motor being bad and somewhere there must be a thermal switch perhaps inside the motor that just shuts it off when to hot. It is free spinning when it is not running but for some reason it is hotter than the other two units so perhaps it has a bad bearing seal.
Anyone ever take one of these apart? Wouldn't want to replace the motor if it is good, besides I hear you can not get replacements.
So I guess at this point it means taking the motor out and looking to see if there is a seal that could be replaced and re-lubed. Maybe??

Brad

RE: AC Puzzled - Brad Townsend - 07-22-2016

Here is a pic of the shaft

RE: AC Puzzled - Richard - 07-22-2016

Brad,

Yours may be different. I took one of those motors apart when it failed to start. The one I took apart had oilite bushings not bearings. I suspect the someone has tried to lube the bushings. The motor I disassembled did not have seals.

But I am all confuseded. My memory chips are corrupted. I think the condenser motor in the Dometic unit that I worked on was a squirrel cage, and the picture shows a fan style I think.

Does that motor have new start and run caps? I have gotten lost in this thread. If not, I would replace them, or switch them with a good unit before tearing into the motor.