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Coleman rooftop unit ac only.

Unit runs fine at night breaks curcuit and cuts off during heat of day

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These units should run in higher ambient conditions within limits. If your unit shuts down with an ambient temperature of 95°F there is a possibility that the system may have a slight over charge of refrigerant in the system or a slight undercharge. This can be easily checked under running conditions by checking the superheat of the gases returning to the compressor. You may also want to check the current draw and the voltage supply during these conditions that are causing the system shut down.

Posted on Sep 23, 2008


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We are in a 5th wheel RV. We have a factory installed Carrier a/c in the kitchen. Lately, it shuts off during the night and we have to reset it in the am in order for it to work. It works fine during...

If the outdoor temps are cooler than inside, AC's are not made for this and will not work well if that is the situation, it floods liquid to the compressor which will overload. will it reset within 20 mins of going off? if so the board/stat are suspect, if not the compressors the villain and its tired and cant handle the other than design condition of 95 F outdoor/80F indoor.

Sep 09, 2011 | Dometic Rooftop RV Air Conditioner


Efficiency of RV Rooftop Units Deteriorating???

If the overall effectiveness of you RV Rooftop AC seems to be much less than the day you bought, here is a simple procedure to keep it running cold and prolong the life of the unit.

1. Air seems to not be blowing as cold as before
2. Compressor trips breaker during the hottest part of the day
3. Air at night works just fine but is lacking during the day

These problems can often be solved by simply cleaning out the condenser coil of the upper unit. You will need a phillips screwdriver and a water hose with a nozzle on it.

- Remove the upper shroud from the unit
- Gently spray water through the condenser coil watching from the fan side. BE CAREFUL, do not spray with too high of pressure nor sideways. Make sure you keep the nozzle spraying directly at the coils.
- Once the water begins to flow clearly through the condenser, you should be good to go. Make sure you get as much of the condenser clean as possible.

This will save the life of many RV Air Conditioners.

on Jul 05, 2009 | Dometic Rooftop RV Air Conditioner

1 Answer

Rv ac throws the breaker when outside temp gets high, unit works fine at night when outside temp cools down

Clean evap and cond coils
Place hand on a/c if too hot during the day but cool at night
then freon is being restricted in the condensor
Cleaning coils may help days
Put a trickle of water on the condensor during the day for a test.

.If this was helpful please rate me.
Leo Ponder Appliance-Tyler,Texas

Aug 07, 2010 | Dometic Rooftop RV Air Conditioner

1 Answer

I have a rooftop coleman ac unit on my RV. It works good at night but in the day when its in the 90's the fan runs but the compressor cuts in for abot 2 sec, and kicks out and the is an electrical odor...

Sounds like your "Compressor Run Capacitor" has cooked. Need to replace it, but not something you should be doing if inexperienced with capacitors and electrical. Capacitors store voltage at a higher rating such as 250-370volts, and can give a fatal shock if not handled properly. Technician, or electrician should only charge about $25-$35 for part, and 1/2 hr. labor to replace it. Just watch for Bees/Wasps when removing the cover on roof, to get to it.

Jul 19, 2010 | Dometic Rooftop RV Air Conditioner

1 Answer

My rv air conditioner works fine at night but only clicks on during the day for about three minute intervals. It seems like the compresor should work harder during the peak heat.

First thing I'd check is the hydro supply to your RV. Test voltage at both times and see if it is the same. You can even buy a plug in tester if necessary, that plugs in to receptacles. It may be a case of everyone around you has AC etc on during the day and your incoming voltage has been lowered, thus AC will not work correctly, and at night when some others are off, your voltage comes back up to where AC will function properly. Especially likely if you are near the end of a power cable run. If you have access to a good generator even temporarily, try plugging into that during the day and see if it doesn't make a difference.

Jun 14, 2010 | Dometic Rooftop RV Air Conditioner

1 Answer

No heat at night

You have a poor low voltage connection from the thermostat or a bad contactor.The contactor is the main relay control inside the condensing unit. The incoming voltage wires connect to it.
Contactors are inexpensive. I would change that first.
Check all your low voltage wires in the condensing unit for loose connections.

Dec 11, 2009 | Coleman Heating & Cooling

1 Answer

Rheem RKKA048JK10X Furnace/AC Unit. My rooftop

Mr. Miller,

It may be a problem with the tubing from the inducer to the pressure switches. During the night hours, condensation forms and collects in these tubes preventing the pressure switch from closing when the inducer motor starts. Check these tubes and possibly re-route so there is no sag in the middle. Try to route them so they are as straight as possible. If that is not possible, at the location of the sag, cut the line, put a "T" fitting in and attach a piece of line to the bottom of the tee with a plug to catch the accumulated condensation.

Also, have your service company check the firing rates, gas pressures and temperature rise across the heat exchanger, Any of these can also cause a problem with condensation accumulation in the pressure switch tubing.

Nov 10, 2009 | Heating & Cooling

1 Answer

My rooftop Trane A/C unit shows high humidity on the thermostat, will not cool the house during the day but cools fine at night. What could the problem be? Also, how can I lower the humidity in the house?

High humidity causes Icing of the cooling coils. Avoid constant running of the a/c. Meaning let the AC pull the house dow 2 - 3 degrees at a time.. The unit shutting off will allow the ice to melt. Make sure the drain is clear by going outside and chkg for drainage. Once the house is reasonably dehumidified the ac can be set and left on its own.

Jul 06, 2009 | DeLonghi Trane 5t Rooftop Air Conditioner...

1 Answer

My duo therm air conditioner works fine in the moning

If the unit has been serviced recently and they added refrigerant to it, then it's possible that they overcharged it causing it to have high head pressure which will increase the amp draw enough on a hot day to trip the breaker.If the unit hasn't been serviced, you might won't to check the condenser coil to see if it's dirty, if its not dirty then check the voltage to the unit, if you're in an RV park when everybody there is running there ACs the voltage may be to low for your unit to run. What fan speed are you running on you may need to run it on high speed during the day.

Apr 24, 2009 | Dometic Rooftop RV Air Conditioner

4 Answers

Duo therm air conditioner

my duo therm air works beautifuly all day but at night when we go to bed it seams to turn on and shut off rapidly. what could be wrong?

Jul 06, 2008 | Dometic Rooftop RV Air Conditioner

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