Forum Discussion

Camper_Jeff___K's avatar
Jun 19, 2018

VIDEO: Installing an AC Coolingstat for temperature control

VIDEO: Installing an AC Coolingstat for temperature control

When in use, my Truck Camper AC unit is either on or off. It has no temperature regulation that shuts the AC off when the desired temperature is achieved. I installed a line voltage, single pole coolingstat, KING K101C, $40.00~, wall mount type, to the AC ceiling junction box, to see how it would work. It does work but I think the regulation of temperature would be better if the coolingstat were mounted to an internal side wall not directly heated by outside sources like the ceiling. I plan to relocate the coolingstat down near the breaker box shown in the video which I think will be a good non-interfering with other things location hopefully taking advantage that cold air is heavier than hot air and will drop down to the proposed coolingstat location. My AC unit seems to be able to lower the internal temperature down about 20 degrees F from what the outside temperature is so a limitation is that in practical use, I will have to not set the unit for more than 20 degrees F below the outside temperature or it may simply continue to run as it does now. I hope it will be better on those plugged in nights in hot areas so we can set it and forget it.
For normal fan or heat strip operation, turn the coolingstat set temperature all the way down and it will be in a run all the time condition down to 40 degrees F. The AC unit is generally only operated in summer so it shouldn't really be an issue since for heating I use either an electric baseboard of the main furnace.

J&K
  • ardvark wrote:
    If your AC is constantly running and does not drop the temperature adequately it is undersized. If it is too cold and the unit does not shut off, the control that sets the temperature is not working correctly and should be replaced. It is an easy replacement. The advantage of a working factory control is it does not shut off the fan so the continual air circulation is helpful in maintaining an even temperature.

    I think the Coolstat will do what a correctly working control should be doing, but it also will shut off the fan, if I understand its operation correctly. I have had to replace them over the years, but they tend to be pretty reliable so it has not been often. I am not sure whether any of the controls off the new remote control units could be swapped in, although I suspect it would be possible with some research on the schematics.


    My brother and I have the same situation with our Dometic 13.5K BTU units. It gets cold inside but both units run all the time. Compressors kick on and off, but the blower fan motor never stops. If your unit shuts off and is silent and cycles on off fine. Ours do not .
  • If your AC is constantly running and does not drop the temperature adequately it is undersized. If it is too cold and the unit does not shut off, the control that sets the temperature is not working correctly and should be replaced. It is an easy replacement. The advantage of a working factory control is it does not shut off the fan so the continual air circulation is helpful in maintaining an even temperature.

    I think the Coolstat will do what a correctly working control should be doing, but it also will shut off the fan, if I understand its operation correctly. I have had to replace them over the years, but they tend to be pretty reliable so it has not been often. I am not sure whether any of the controls off the new remote control units could be swapped in, although I suspect it would be possible with some research on the schematics.
  • ardvark wrote:
    Okay, I am totally confused. The video says the AC is either on or off and has no temperature control. That is simply not true. The knob on the left side selects the mode, fan, high or low cool etc. The knob on the right sets the temperature the AC cycles at. My AC turns the compressor on and off depending on how I set the temperature. I can set it so my camper will freeze me out, or hardly cool at all. Every rooftop unit I have ever worked on with the controls in what is called the air box works this way.


    My AC unit is always running when it is turned on. There is a dial to set the amount of cooling but the unit runs constantly until it is turned off. The purpose of the coolingstat is to shut the unit off when the desired temperature is achieved, then cycle on and off to maintain the desired temperature.
  • Okay, I am totally confused. The video says the AC is either on or off and has no temperature control. That is simply not true. The knob on the left side selects the mode, fan, high or low cool etc. The knob on the right sets the temperature the AC cycles at. My AC turns the compressor on and off depending on how I set the temperature. I can set it so my camper will freeze me out, or hardly cool at all. Every rooftop unit I have ever worked on with the controls in what is called the air box works this way.