2nd air conditioner help

[Hawkpat]

We've been out for about a week with no problems but yesterday noticed bedroom a/c wasn't coming on. Have the dometic controls and checked on mode and zone 2 was on fan but unit not running.

Last night it never came on though zone 1 unit running through duct kept bedroom cool.

I have turned thermostat down to 55 and it still does not run.

Checked circuit breaker and it seems fine.

Any ideas? Thanks.

[bncinwv]

You stated that the thermostat was set on fan? It needs to be set to cool for the air conditioner to work. Then you can set the fan (some recommend on high to prevent the ac coils from freezing) depending on outside temps and humidity. If the thermostat will still not start the ac, I would recommend checking if the unit has froze up. You can remove the shroud to check.
Bingo

[Hawkpat]

I got the fan to run after putting it on that setting. Will that help the coils to unfreeze if that is what the problem is?

[1retired06]

You might consider shutting the AC off for a period of time, that will unfreeze the coils if that is the problem, and then restart.

[Hawkpat]

The ac is off. I just have it running on fan. Should I turn the fan off as well?

[Artemus Gordon]

Noticed exact same issue this weekend. I am still on the learning curve with both AC units, but was surprised how cool the bedroom stayed with md ship unit running alone. I am very concerned about freeze up with our 115 degree weekends. Set zone one on med fan not automatic and it ran all the time. On auto fan, zone one does cycle but not always. My mid ship unit was having trouble yesterday keeping front LR cool. I put on high fan after shutting off a half hour. Seemed to help. One more trick, we ran front LR fantastic fan on lowest setting and room cooled right down. Think heat builds up in that area and needs venting it also seems to pull cool air forward!

[lasater]

Hawkpat,

Having the fan run while the compressor is off will help defrost the unit (assuming that ice coating is your problem). If you can feel air movement with the fan on, then it is probable that your unit is NOT frozen. The ice would prevent any air movement.

It is obvious that you have power available on the unit, so that is not the problem. You might check with Ozz by PM. He is the MOC member who is the most knowledgeable on A/Cs. They are his specialty.

[Hawkpat]

Thanks for all the help. I'm kind of like artemus - new to the unit and working with two ac's. I ran fan for a while then shut it off. When I started it back up it worked fine the rest of the trip. It was hot and humid in San Antonio. Don't know if that contributed.

[DQDick]

Never set the fan on low if the AC is running, it will freeze up. Always clean your filters regularly (the green filters under the access panel in front of your air dump) and once a year at least (more if you're near cottonwood trees in the spring) hose your coils on the roof. I have my calendar on my phone set for some of the regular maintenance items such as cleaning the filters, recharging the water softener, etc and that way it doesn't get away from me.

[Ozz]

Agree with Dick on the low speed fan

[Hawkpat]

How about setting the fan on auto?

[Montana Sky]

I've had a 15k btu in the living room and a 13.5k btu low pro in the bedroom for the past 8 years. Last week we had temps into the 108's with a heat index of 116 thanks to the humidity. I always run my a/c units in the "on mode", never on auto during the heat of the day. I also leave the "dump" screen open instead of using the ducted feature. To me using these methods allows the cold air to immediately leave the a/c unit and seems to have helped keep the units from freezing up. So far I've never had an a/c unit quit or freeze up in the past 8 years. At night, I will flip the units back to auto mode just to make sure I dont freeze myself out while sleeping.

[richfaa]

Have both of the ducted A/c is the new Big sky set on auto.They have been running all week with temps in the 90's and high humidity.Not a problem.Always ran the 06 on auto..never a freeze up, never a problem.....

[steelpony5555]

I must be lucky too cause I have never had an AC freeze up. I run my current one on Auto all the time and the bedroom on low, and on my last trailer I would run it on low.