A/C problem

So does anyone know how to do the diagnostics on the panel board?

Thanks for all the replies. It's funny how the tech appeared to know everything about the unit but never said what y'all are saying....that this is normal. His response was always "don't know why it's doing this"!! It is a digital thermostat.

Thanks to the OP for motivating me to do something about this. It actually was keeping us awake in the night on the last camping trip. On a sunny day with hot weather, it's not noticeable because the AC just runs continuously.

Our Dometic AC does the same even at low outside temperatures at night when it only needs to run infrequently. In auto, it runs on low for a while, then the fan goes off while the compressor continues to run for 5 seconds, then the fan comes back on high for about 30 seconds, and then the whole thing shuts off for a while. There is no doubt in my mind that the temperature never gets more than a degree or two from set point. It does not make sense to me that this is the auto special feature. If Dometic can’t come up with a fix, I’ll rewire the whole darn thing to run on a residential thermostat—no this probably won’t be the simple re-wires that have been posted on this site.

See page 8 & 11.

http://www.dometic.com/QBank/EPiServer/Dometic/US/Manuals/RV-manuals/Air-Conditioning/Single-Zone-LCD-Operation-Manual_17590.pdf

Durhamcutter wrote:
We have the same problem, it is your digital thermostat and two Tecks have told us that it was suppose to do that. I don't like it either but it how it is suppose to work, don't know why they just said that it was the digital thermostat. Good Luck and happy camping

I guess that is why the call it a "special feature", the problem seems to be when the temperature is right at the change over point between hi and lo, they should have done something different with the software in the T-stat to prevent this.

The work-around is don't use AUTO until the temperature is reached in the RV and has stabilized. My New RV in my sig. has done this since day one. I have 2 units with separate T-Stats and they each do this.

We have the same problem, it is your digital thermostat and two Tecks have told us that it was suppose to do that. I don't like it either but it how it is suppose to work, don't know why they just said that it was the digital thermostat. Good Luck and happy camping

Might also be a bad fan motor. Those bushings are famous for seizing up.

I don't think so.......

Larryect wrote:
Mine operates as Learjet described. Shuts down the fan for a few seconds when changing fan speed when fan is in auto.

Ok...so is there a bunch of defective control boards for the Dometic AC's ?