20 Most Recent Dometic Rooftop RV Air Conditioner - Page 8 Questions & Answers

I think you should try it out first to see.

You need to borrow a clamp on style amp gauge, and check amp draw on black wire in box where hydro wires connect. (PLEASE, be careful, and if not experienced in this type of test, don't try it, due to likelihood of getting a shock. ) If it's the compressor kicking in that's causing the breaker to trip, and capacitor is good, then it's usually a problem with either low incoming (supply) 110-120 AC voltage, which will cause high amperage draw, or compressor on it's way out causing high amp draw. If it's only drawing 15-18 amps, and your tripping a 20 amp breaker, then breaker is getting weak.

It is possible that a sudden loss of power caused the fan to run backwards. Usually that happens to a compressor, not a blower but I can't think of any other reason. May consider installing a time delay (delay on break), right on the red to the tstat rather than yellow, to ensure everything is included in the delay. Most newer tstats have them built in, possibly upgrade tstat. If you need further help, reach me via phone at https://www.6ya.com/expert/thomas_092728000e6acb79

I have a dometic 13500 BTU Roof mount a/c. It is set up with the duo-therm analog thermostat. The system cools fine. The problem is that the a/c gets down to the right temp, then it turns off like it should but turns right back on within a few seconds. Any help would be greatly appreciated.

Your unit have dirty coil.
Shut unit off and clean the coil also change filter for indoor unit .Unit is shutting off on high head pressure

Your wire size and breaker is correct and should be fine as long as all connections are tight and plug and receptacles are OK. Does any part of the wire get warm? Check the temperature of the plug (plugs/sockets) and cable at each end.

Make sure your tstat is programmed for electric, not gas. Or in the settings you want that the TSTAT CONTROLS THE FAN. If you need further help, reach me via phone at https://www.6ya.com/expert/thomas_092728000e6acb79

Is this tstat battery powered or does it have a common wire? How many conductors are inside the tstat? If you need further help, reach me via phone at https://www.6ya.com/expert/thomas_092728000e6acb79

If the unit is a 220v, you will see 110v on that unplugged wire you mentioned. If it is 110v system then you probably have a swollen or open capacitor. The lil black box on the control board is a micro relay. And they do act up in different ways. If it's clicking, normally, that tells me its working. If it's 220v, make sure you have 220v to the system. If you have 220v to the system, and no power goilg through the micro relay, you can try jumping by that relay. While it's plugged into the relay (both wires), touch the 2 wire ends together with the end of a screwdriver for a second or 2 and listen for the comp to start. If it does you found your problem. All this does is bypass the relay by connecting those wire together. I've seen these units not work, if there is 2 units on the roof, due to a safety that doesn't allow both to operate at the same time, and never found the reason why. Now if it's 110v, you'll need to dig a bit more, following your voltage. Source, line, load. The source volts enter, the line feeds to the switch(s), the load is the motor/comp. The capacitor is a round/oval metal cylinder with wires attached, and stores voltage so it must be discharged by shorting the terminals to each other or ground. POWER OFF FIRST! Be safe please. If its 220v and you only have 110, check the breaker(s). If the capacitor is swollen up on top, where the wires connect, or have this sticky oil coming out of it, it's damaged. More that likely its the board. Last 1 changed was $129 my cost, not the customers. And I had to rewire the unit a bit and change the tstat also. So if you end up buying a board, ask them about an exact replacement. If it's not, ask them if they can draw you a schematic to help. Hope this helps!

Radio shack should have a transformer that will work bring the board in with you. Also try R.V. junk yards they have a lot of good used parts off of wrecked rv there is one on lincoln in Phoenix a many more go online and look up used rv parts.

thermostat or relay module