Having a problem with a Coleman roof top A/C unit. After about 2 hours the coil freezes up. Have any of you had this problem and what would be the problem. We have already verified that it is not low on refrigerant. I think that maybe a relay may be stuck or a sensor on the coil is not operating.
Other things that will cause ice are clogged filters, bad fan motors, to many closed registers (vents), dirty filter, running the system when it is "too cold outside" (below 65 degrees F) or dirty coil.
2005 Xterra off road 4X4, 2007 26' Aluma-Lite, WD w/ friction sway, Prodigy, Yamaha EF2400, 400w inverter, front carrier w/ rod holders, Dish Network
High humidity will also cause the problem that you write about. Open one of the roof vents about half way and try the AC unit. The open roof vent will allow the humidity to go out and the AC unit will not freeze up. I had a lot of freeze up problems when camping along the Colorado River. Opening up the roof vent solved the problem.
You may want to pull the roof cover and then check the exterior coil to see if they are dirty and/or plugged up. Also check the coil just above the filter, if they are covered with dust and dirt, you won't get good air flow and you will get freeze up.
Steve & Linda
Son married (1 DIL, 3 granddaughters 1 grandson)
Daughter in College
Miami CO. Kansas
2004 F350 CC dually 8ft bed 6.0 PSD
2009 Bighorn 3670RL
B&W under bed hitch with 18k companion hitch
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