Dometic A/C issues

dperrilloux · 09-29-2013, 04:16 PM

Ok all I need some help. I am new to the whole forum thing so please excuse me if I do something wrong. I have a Dometic 13500 BTU ducted system in my 2 year old 26 foot camper. Last year the circuit board in the A/C fried on an electrical spike. It was replace as well as the thermostat and everything has worked fine until three weeks ago. Now when i turn the system on the blower comes on and approx. 30 seconds later the compressor turns on. It starts cooling and runs for about 2 minutes with the compressor turning off and the blower continuing to run. the camper does not cool down until late at night. it as if the compressor is not running long enough. When it does cool down the system will turn off and on every three to 5 minutes all night. The next day the issues repeat. I am out of warranty and want to try and repair myself is possible. Has anyone else experienced this issue.

jimh · 09-29-2013, 04:51 PM

my first thought is low freon causing short cycle.

before i would get into that, i would try another thermostat.

there is also a temp sensor on the evap coil that could also be the problem. i would eliminate the wall thermostat first.

markb5900 · 09-29-2013, 04:54 PM

Agree with the above. I would try a new thermostat first.
Is your fan set to auto on your thermostat?

dperrilloux · 09-29-2013, 05:09 PM

The thermostat is a single zone three option digital stat with Fan, cool and furnace options.

markb5900 · 09-29-2013, 05:10 PM

On the fan option, does it say AU, or Hi or Lo?

cfsoistman · 09-29-2013, 05:12 PM

Fan contiues to runs since the t-stat isn't satified. Compressor may be kicking off due to high head pressure. Dirty filter or dirty indoor evaporator coil. Could also be outdoor condensor coil on roof. Before replacing parts check these out. Unplug the camper before taking the top off the AC Unit. That's where I would start.

dperrilloux · 09-29-2013, 05:19 PM

Quote:

Originally Posted by markb5900

On the fan option, does it say AU, or Hi or Lo?

It gives me all options through the temp up down buttons.

dperrilloux · 09-29-2013, 05:23 PM

Quote:

Originally Posted by cfsoistman

Fan contiues to runs since the t-stat isn't satified. Compressor may be kicking off due to high head pressure. Dirty filter or dirty indoor evaporator coil. Could also be outdoor condensor coil on roof. Before replacing parts check these out. Unplug the camper before taking the top off the AC Unit. That's where I would start.

Thanks for the options but I have completed all of the above. Everything is clean. I am really leaning toward the sensor in the evaporator. The evaporator is clean but not getting cold. I guess it could be the compressor but seems to be electrical.

markb5900 · 09-29-2013, 05:28 PM

Quote:

Originally Posted by dperrilloux

It gives me all options through the temp up down buttons.

As it should, just wondered what you had it set on.
Do believe it is is something in the compressor/evaporator. But wanted to make sure it was in auto and not hi or lo as the reason the fan kept running.

dperrilloux · 09-29-2013, 05:31 PM

Quote:

Originally Posted by markb5900

As it should, just wondered what you had it set on.
Do believe it is is something in the compressor/evaporator. But wanted to make sure it was in auto and not hi or lo as the reason the fan kept running.

It is on Auto.

jimh · 09-29-2013, 06:31 PM

Quote:

Originally Posted by dperrilloux

Thanks for the options but I have completed all of the above. Everything is clean. I am really leaning toward the sensor in the evaporator. The evaporator is clean but not getting cold. I guess it could be the compressor but seems to be electrical.

That low temp switch is on eBay. U should be able to pull it and test it with an ohm meter and some ice. It looks like a frost free frig defrost temp switch (shuts off heater when temp gets too high). This would open if temp gets too low. The dometic rep at the last rally was telling abt it. At $30 on eBay, I believe I would make sure that is really the problem. I would also check at a local "appliance parts" for a cheaper alternative. U can probably beat that $30 price.

dperrilloux · 09-29-2013, 06:45 PM

Quote:

Originally Posted by jimh

That low temp switch is on eBay. U should be able to pull it and test it with an ohm meter and some ice. It looks like a frost free frig defrost temp switch (shuts off heater when temp gets too high). This would open if temp gets too low. The dometic rep at the last rally was telling abt it. At $30 on eBay, I believe I would make sure that is really the problem. I would also check at a local "appliance parts" for a cheaper alternative. U can probably beat that $30 price.

I found it at rv part wholesale for 15.00. Thanks

JohnandPandra · 09-29-2013, 07:21 PM

It sounds like it could be a weak overload on the compressor, weakend by that spike. It would be on the compressor under the cap by your connections. Not very expensive to replace either. You would have to take it off and go to the local parts house that has sells small compressors to match it up. Good luck.

jimh · 09-29-2013, 10:16 PM

$15 sounds more like it.
i had the thermostat call for the compressor to shut off while the fan continued to run. on mine, the thermostat would drift. replaced it and all is normal.
the low temp switch seems to be a low maintenance item. the dometic rep is the first i had heard of it going bad.

don't overlook what johnandpandra posted. may want to make sure connections are not loose while ur in there.

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