A/C Ignores Thermostat?

[jim.smithjr]

Our rear roof top A/C works perfectly, but the front one doesn't. Recently it has begun to run constantly, no matter what temp is set on the thermostat control. The only way to shut it down is to turn it off manually.

I also think it isn't cooling as well as the rear unit. The air coming out of the front grates doesn't feel as cool as the air coming out of the rear unit's grates.

Could this just be low freon, or what do you suggest?

[itdave]

Make sure the fan setting for the front zone is on Auto, not low or high.

[roscoesdad]

When this happens, pull the inside grill off and see if the evaporator is iced up. If it is, open the vent in the inside grill, and let the air dump directly into the MH instead of flowing through the vents. Also, turn the fan on high. Mine iced up numerous times when the outside temp was above 90 and the humidity high. Doing this solved my problem.

[jim.smithjr]

Thanks Dave....you were right! As soon as I saw your reply I was pretty suspicious. Today I moved the motor home and "tested" the front A/C. Sure enough the fan was set on high.

I love a cheap fix...and they are such a rare event around one of these beasts!

Thanks again, you made my day.