Air Conditioning problem

[Nick Badame Refrig/ACC]

Hi Jim,

Theese boards go bad, usually the contacts in the relays corrode or weaken which makes them

spark when energized. That spark ends up welding the contacts together. If you need a new board,

just give me the model # and serial # and I can ship it out.

Nick-

[jjrbus]

I cant &*%##& belive it. The fan on the second AC just stopped working!!!!!!!!!!!!!
This is in FL 90 degrees and 90% humidity.

[Nick Badame Refrig/ACC]

Hi Jim,

Don't get too upset, A/C's are not worth getting aggravated over....

Start by, testing if you have current going to the motor, is the motor real Hot!   

If not, backtrack to the source and elliminate things as you go. capacitor, relay, switch, burnt wires,......

Nick-

[JackConrad]

I cant &*%##& belive it. The fan on the second AC just stopped working!!!!!!!!!!!!!
This is in FL 90 degrees and 90% humidity.

Jim,
   If it gets too hot for you & Josephine, use our house or the cabin until you get it fixed.  Jack
PS: Since the second AC also failed, check the shoreline voltage. Low voltages increaqses the amperage.

[jjrbus]

I'm not upset, I seriousely contemplated useing a sledge hammer on AC's but it's too hot out.
Thanks to your help, I now have 1 running AC, the original one that quit. With nothing to lose I took the circut board from the 2nd AC, that is the one where the fan stopped running. I put the circut board in first one where the fan was not running but compressor would not shut off. Your internet diagnostic was right it was the compressor relay. It is running, blowing cold air, turns on and off everything there is fine.
Now to figure out 2nd one. I have no board for it at the moment. Befor ordering board, I would like to make sure that the fan motor is good. (its the fan that stopped running on this one) Running power to the fan motor has me a bit perplexed there are 6 wires running to the fan. Which ones would I have to apply power to?
1    green    Ground
2    brown    fan terminal of run cap
3    white     C terminal of run cap
4    red       circut board in AC unit   fan low
5    yellow   circut board in AC unit  terminates hooks to nothing
6    black     circut board in AC unit  fan hi

It seems that if fan motor and board are bad it might be better to just replace whole unit. Just guessing but fan and board must be up near $200.

Thanks Jack and Paula, Josephine andI truly appreciate your generosity and friendship.

[jjrbus]

Also when I shorted across capacitor terminals I expected to see a spark. None was present?

[Nick Badame Refrig/ACC]

Jim,

Sometimes the capacitor discharges it self. First, if you have a ohm meter you can test the capacitor.

If your meter has an audiable sound. the capacitor should sound briefly and then drop out. It's good!

If not, then the capicitor is bad.

To test the motor, send 115v to black "high" and white "nutral" while the capacitor is still in line.

Listen for a humm if the motor doesn't start, or will it start if you give it a spin by hand.

Let me know
Nick-

[jjrbus]

 Thanks Nick, will play with it in the morning.

[belfert]

If you can swing it, I would just replace the broken A/C unit.  You now have a bad board and a non-working motor. 

If you shop around, you can get A/C units pretty close to $500 shipped with inside unit.  You can possibly get just the top unit and not have to pay the $75 or so for the inside portion.

[Sojourner]

Jim.......While I was typing this post...Nick has answered capacitor testing post.  Capacitor's life are limited to higher than design heat environment. Keep that in mind.....it may still test good "cooled" but fail in hot condition such as 120°F or higher.

You cannot run test a permanent split capacitor (PSC) fan (unless you spin it by hand) or compressor motor without an good starting capacitor....Period!
So if you want to replace capacitors, which is usually under $10 each and same time check for welded relays points via ohm meter with wires disconnected. If not infinity...welded points.

However...your problem maybe due to low voltage source which Jack had already mention. It should read at least 110v or higher the better...up to max spec (whatever label quote). Otherwise motor's will get extra hot to a point of burnout winding and cook out the fan's bushing or ball-bearing lube to run dry. And if it still working in low voltage...it will work harder with less cooling differential (between air intake & output)

I suggest to go ahead and replace inoperative A/C unit for new one and perhaps second unit...be ready for another one too.

Bottom line is to keep checking your power source for good voltage input....while in high load (ampere).

PS...I was rewinding electric motors for business in 1958 but choose to go MSU (East Lansing, Mi) instead.

FWIW

Sojourn for Christ, Jerry

[TomC]

I personally would not spend more than a couple of hours on this project, and no more than $200.00 since you can just buy a new unit for $5-600.00 and be done with it.  Good Luck, TomC

[jjrbus]

 There are reasons not to buy new AC. If I was on road, its not an issue just buy new!
But now I have the resources and the luxury of time. If I just buy new AC I do not learn anything. I enjoy helping people, it makes me feel good and now have the opportunity to let other people feel good by helping me. I enjoy the interacting with other people and maybe these posts will help someone else.
I recently inspected the same AC as mine (I did not think to pull the boards or caps, shame on me) That was replaced because it was not working well. The evaporator coil was 60% blocked with dirt. Was that the problem? well it was not helping any!  I would have cleaned the coil to see if it was the problem. I would hate to spend $500 because of something simple!!
If it is the board and fan motor, it is not an issue just replace the whole unit. No sense in putting $200 in a $500 unit.

[gg04]

Not just low voltage issues in areas that have suffered hurricanes....Ours and four of our neighbors have had had transformer malfunctions this spring we came back from a car show and my bus had turned its shore power connection off because voltage had jumped to 143 volts . without protection this will burn out motors and anything running on a transformer...gg04

[jjrbus]

Thanks for all the help. I hotwired fan as per Nick, fan started right up, no delay, no hum nothing. Just started running! It seems problem is some where else.
Voltage here is averageing 121+ volts.
Need to get ahold of Nick to get a price on board. Its a Dometic 3104757.004 .
Should also replace capacitators while I'm up there!

[Nick Badame Refrig/ACC]

Jim,

is the mo# of the whole A/C "57915"? this way I can look up the Capacitors

Call me... 609-263-2296

Nick-