Air Conditioner Failure?

[Captain Morgan]

While camping at Stone Mountain Park, GA last week, our front A/C unit started acting up. The symptoms were similar to what others have posted about on this form. The fan would run, but the compressor would try to start and then immediately shut off. So, after some research and investigation I found the unit had iced up. So I shut it down, cleaned all the filters and let it thaw out. I started it up again and everything appeared to be working fine. BTW, the voltage was fine and it never kicked the breaker. We left to enjoy some of the activities in the area and upon our return later that day discovered that it was warm inside and there was a slight smell of a hot electrical component much like when a transformer fails. The unit was blowing warm air and sounded as if it was laboring. I immediately shut it down. We didn’t use the unit for the rest of our stay and now that we’re home, it’s time to figure out what’s wrong. Before I take it to the repair shop, I’d like some guidance on how to narrow down what the problem might be and if it sounds like a repairable condition or a new unit is more likely.


Thanks,

[BAins]

Well if the filter and coils are clean and unit is freezing up, that sounds like the unit is low on charge (refrigarant). As for as the compressor not starting it problaly was over heated and tripping out on the overload. Will the unit come on and run now? dirty evap coils could make one act as if was low on charge. make sure they are clean. A roof top unit like these do not have ports to put gauges on. You can find a service man to add a port and recharge the unit, but he may not be able to find the leak, or fix it. does it still try to cool, or is it completely out of refrigarant? Most rv places would replace the unti instead of recharging. Hope this helps feel free to ask any qustions. I will try to answer. Brent

[RV Wizard]

Bob, most likely place to start is the compressor start capacitor and starter. I am not sure as to what make and model air conditioner you have but most likely these components will be on the top side of the unit. Make sure power is off before evaluating the situation. Remove the shroud and control box cover. The start capacitor will be a round black Bakelite cylinder with some wire terminals on top. The compressor motor starter (positive temperature coefficient resistor) will be attached to it.
The freezing up can be one or a multitude of small issues. Check the amperage of the unit when it has been running after about 5 minutes. It should be in the area of 11 amps for the compressor. If you are near this amperage the refrigerant level is good and you have other issues. Check the divider between return and discharge air as this can cause freezing of the coil if the air is short cycled back to the evaporator. Be sure to use high speed in humid weather and not set it to run too cold. Good luck and let us know what you find.

[Captain Morgan]

Thanks for the advice, I won't be able to troubleshoot the unit until this weekend. So, I'll take the advice you guys have provided and then let you know what I find.

Thanks again,
Bob

[TXiceman]

Also check your voltage when you are doing the diagnostics. Most will woek down to 108 volts OK and lower, you will start having problems.

Ken

[Captain Morgan]

Well, I started troubleshooting my AC problem and found that the Start Capacitor is fried. The wiring and connections all look great and the coils are completely free of debris and don't have any damage. So, here’s where I need some guidance. It’s obvious the Capacitor and the device on top of it (called a PTCR per the schematic) are bad as the PTCR is melted and smells like a burnt ballast. It seems based on reading other posts that this is a fairly common failure. Will just replacing them put me back in business? Is there something else I should look at before I replace them? Should I replace the other two capacitors along with this one?

Assuming I just need to replace them, where do I get the replacements?

Here’s the information I have.

The AC is a Coleman Mach A/C model number 863388766 on a 2003 Fleetwood Pace Arrow.

The Capacitor has the following information
Mallory
88-108 MFD 165VAC
1497-086 235=0220-04

The Positive Temp Coeficient Resistor (PTCR) has WSX-5ACM on it. I can’t make out the manufacture.

Thanks for all the help,
Bob

[BAins]

Just replace the one that is fried. No need to replace the others. Go to a local electrical supply store. They need to know 88-108 MFD 165VAC. Stores around my area that carry such animals are Johnstone supply, baker dist., Southern Electric, Southern Pipe and supply, and Lambert electric. Once you replace the capictor just turn t on and enjoy cool air. I still wonder about your commit about it being froze up though. good luck and talk later. Brent

[RV Wizard]

Bob, you will also need to replace the PTCR, as I am sure you are aware of this. Do you have a local RV parts and or service facility near you? They are a source. If not you may want to try http://www.pplmotorhomes.com/parts/r...ccessories.htm

[Tincup]

You might want to check out this site as well, they sell a hard start capacitor that is supposed to help is starting the compressor. http://www.arnoldservice.com/compres...t_boosters.htm

They also have a lot of good information on A/C in general.

[Captain Morgan]

Thanks for the advice and links. I've been away the last few days (family reunion up North) and haven't had a chance to get on the computer. I'll be making some calls tomorrow to get the parts I need.

Bob