Coleman Mach a/c unit not working right!!! Help please???

Gentleman thanks so much for the information. Doug you are correct and I see your point there is no way for me to see if amp draw is correct. What I have done is pulling the thermostat worked it and finally got it to start clicking and watched it’s operation. I thought that was the problem but it did the same thing again. So what I am thinking is the following.

As I have stated I have (2) a/c units on this camper. One that is not having problems or cooling all the time services the main section of the camper and is ducted. This one has a wall thermostat And senses temperature better for the room. It runs non stop on the hot days of summer. The (2) one is the one in the bedroom that is cooling then blowing warm then cooling again.

Main a/c is Coleman mach 15,000 btu

Bedroom a/c is Coleman mach 13,500 btu.


What I believe is happening is the bedroom system is cooling maybe a 10x10 room only with (2) vents right off the a/c. The one side is blowing against the wall where it connects to the bathroom. So with everything else working right and the thermostat working, I believe it is cycling due to the a/c being to big for that area and recycling it’s on cold area at the unit.

So in other words blowing 55-57 degree air with a maximum of 1-1.5 foot from the door/wall. So that cold air is getting back to the a/c and cycling off the compressor. Now the room is 75-80 degrees but that’s the whole room. The thermostat cooper wore is on the return side which is facing the same way as the wall that cold air is hitting. While I may not be correct it’s the only thing that makes sense to me. Thoughts???

duckman2018 wrote:

dougrainer wrote:
I repeat, HOW do you know it is pulling the correct amps? You should hear a click when you turn the Tstat knob, so yes, zero in on the tstat. You can jump the 2 wires at the tstat to verify the Tstat is the problem. Doug

Doug thank for the advice. I don’t know if the thermostat wires are pulling the correct Amps just the fan motor and compressor. This thermostat is built into the housing not on the wall. When I turn the knob I don’t here anything but feel a click when turned to almost all the wall warm or red. Which wires can I just out on the manual thermostat inside the a/c?

I am going to repeat, HOW do you know about the AMPS???????? There is NO way a Novice can state such a thing. You have to have a specialize amp draw meter to tell you amp draw. Amps will not be a factor in your problem. Just trying to get into your mind set about Amps. There should be a Yellow and a White wire on the tstat. You connect them together. MAKE SURE THE UNIT HAS NO 120 WHEN MESSING WITH THE WIRES. Doug

Well my Coleman is also ceiling mount.. My next suggestion is same as Doug's. if that dont' help and the thing is new consult a professional as you will need their support for warranty repair.

Of course it will work 100% with the pro in the house

OH. that's another thought. There is what LOOKS like it should be a freeze sensor BUT IT IS NOT. it's the intake air tempsensor

now with my Carrier controlled Advent air I have a freeze sensor stuck in teh coil.. but on the Coleman the sensor is supposed to hang in free air.. NOT in contact with the coils. That might be the issue.

Careful pulling the grill as when you remove the knobs there is an extension between the knob and the control shaft. Hard to find replacements (I had to fabricate one)

dougrainer wrote:
I repeat, HOW do you know it is pulling the correct amps? You should hear a click when you turn the Tstat knob, so yes, zero in on the tstat. You can jump the 2 wires at the tstat to verify the Tstat is the problem. Doug

Doug thank for the advice. I don’t know if the thermostat wires are pulling the correct Amps just the fan motor and compressor. This thermostat is built into the housing not on the wall. When I turn the knob I don’t here anything but feel a click when turned to almost all the wall warm or red. Which wires can I just out on the manual thermostat inside the a/c?

I repeat, HOW do you know it is pulling the correct amps? You should hear a click when you turn the Tstat knob, so yes, zero in on the tstat. You can jump the 2 wires at the tstat to verify the Tstat is the problem. Doug

wa8yxm wrote:
Two questions.. ONE: have you cleaned the condenser coils outside?

Two. Remote or ceiling mount controls?
With remote there may be a frost sensor in the evaporator coils (Usually lower right corner... Just sticks in) if it's low on Refrigerant (Folks it is no longer Freon (R-12) but something new (134A) then it will "ice up" and the frost sensor will shut it down.

If you are on a 30 amp site and have a load shedder type energery management system (intelletec) it can cycle the compressor too.

Ceiling mount controls. The coils are clean as I reviewed over them yesterday. I am plugged into a 50amp service with no load shedder system. I saw no ice on coils.

Two questions.. ONE: have you cleaned the condenser coils outside?

Two. Remote or ceiling mount controls?
With remote there may be a frost sensor in the evaporator coils (Usually lower right corner... Just sticks in) if it's low on Refrigerant (Folks it is no longer Freon (R-12) but something new (134A) then it will "ice up" and the frost sensor will shut it down.

If you are on a 30 amp site and have a load shedder type energery management system (intelletec) it can cycle the compressor too.

I looked at data plate on the unit and was reading within specs. This is the rear a/c unit which only has temperature/thermostat control at the unit itself no wall hung thermostat just a knob on the unit that turns from hot to cold. When I turn it I don’t here the compressor clicking on and off.

check the t-stat. on/cool/ Fan/auto. That will cycle the with the compressor.
Cool/on fan/on. That will keep the fan on all the time.

How do you know it is pulling normal amps? I would suspect bad Freeze Sensor if the unit has a wall Tstat. Doug