VIDEO: Installing an AC Coolingstat for temperature controlWhen 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

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.

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.

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: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 .

No, my fan always runs when the AC is on which is what I meant by compressor cycling. Often that is preferred as it tends to reduce variation in temperature, but not everyone prefers that as I can tell by your response. What I have been just looking at are 20 amp remote controls that have a relay that will fit in the air box. If there is room, that would make for a really neat install and would be super easy to do. Just three wires into the relay and out to the AC and that would kill every things when the temperature is reached which sounds like your goal. Both Dometic and Coleman both used to offer remote control units, but they are not longer in production, although Atwood (Dometic owned) does offer such a unit. I like to play around with this stuff, so I am going to see what I can come up with. Things are always tight in TCs or there would be more options.

VIDEO: Installing an AC Coolingstat for temperature control

ardvark
Explorer
Jun 21, 2018
I know Lance offered a wall T-stat as an option some years because I looked at a used one about a year ago. You can also find it in the Lance brochures online.
Camper_Jeff___K
Nomad III
Jun 21, 2018
The coolingstat control is going to come in handy on my next trip golfing.
time2roll
Nomad
Jun 21, 2018
Looks like a great improvement to me. I can't stand a fan blowing when unnecessary.
trail-explorer
Explorer
Jun 21, 2018
pbrooks101 wrote:
I have a Lance 1191 and, without looking at the make/model of the A/C at the moment, my fan DOES cycle off with the compressor depending on what my thermostat is set for. On 'auto' mode, the fan cycles off with the compressor when the set temperature is reached. If the t-stat is set to 'hi' or 'low', then the fan stays on that respective setting regardless of the compressor on/off cycling. My A/C is not ducted.

Your's is unique in that it has a thermostat controlling a non ducted model.

From what I have always seen, ducted models are always thermostat controlled, and non ducted models have the controls on the ceiling unit.

A ducted unit controlled by a t-stat works exactly like how yours is operating.
Cool deal that Lance took the effort to have the A/C controlled by a wall mounted t-stat. That's a rarity on most truck campers.
pbrooks101
Explorer
Jun 21, 2018
I have a Lance 1191 and, without looking at the make/model of the A/C at the moment, my fan DOES cycle off with the compressor depending on what my thermostat is set for. On 'auto' mode, the fan cycles off with the compressor when the set temperature is reached. If the t-stat is set to 'hi' or 'low', then the fan stays on that respective setting regardless of the compressor on/off cycling. My A/C is not ducted.
ardvark
Explorer
Jun 20, 2018
Here's the thing about that. You can use the same air box along with the module board and t-stat you normally find for ducted system right on the air box, if you can figure out a way to get 12-VDC to the module board.

The same controls work regardless of whether the unit is ducted and a non-ducted air box is available. So if you can find a way to get 12-volts to the air box, everything else will work. However, I am not sure how a T-stat normally found on the wall will look on the ceiling.
deltabravo
Nomad
Jun 20, 2018
Camper_Jeff_&_Kelli wrote:
Compressors kick on and off, but the blower fan motor never stops.

Normal operation.

My Coleman does the same thing.

Yes, it's annoying having the blower fan run all the time.

Just thought I'd throw this out there as to offer additional clarification (which ardvark was explaining as well)

A ducted A/C, which is controlled by a wall mounted T-stat will turn off the compressor and the air circulation fan when the set temperature is reached. I've never seen a truck camper with ducted A/C though.
ardvark
Explorer
Jun 20, 2018
If all you want to do is get the fan to cycle with the compressor that is pretty easy to do. My guess is just feeding the fan off the compressor lead would accomplish that as the fan draw is not much. However, it messes up the fan control when you just want to run the fan.

I also looked at relays that use 120-volt coils and I think there is space for one, but same issue with fan operation without the AC so you would have to add a Auto/On switch like you have on traditional RV thermostats.

If it were not for the wiring issue of getting to a wall thermostat, going that route would be easy peasy as the saying goes. :)
billyray50
Explorer
Jun 20, 2018
Camper_Jeff_&_Kelli wrote:
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.

Very interesting. Thanks for video. Would like to have my rooftop AC cycle on and off in my TC like my fifthwheel ACs. Looking for ideas.
ardvark
Explorer
Jun 19, 2018
No, my fan always runs when the AC is on which is what I meant by compressor cycling. Often that is preferred as it tends to reduce variation in temperature, but not everyone prefers that as I can tell by your response.

What I have been just looking at are 20 amp remote controls that have a relay that will fit in the air box. If there is room, that would make for a really neat install and would be super easy to do. Just three wires into the relay and out to the AC and that would kill every things when the temperature is reached which sounds like your goal.

Both Dometic and Coleman both used to offer remote control units, but they are not longer in production, although Atwood (Dometic owned) does offer such a unit.

I like to play around with this stuff, so I am going to see what I can come up with. Things are always tight in TCs or there would be more options.

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VIDEO: Installing an AC Coolingstat for temperature control

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