A/C thermostat readings off

[Jberry805]

Just bought a used 2021 high counrty 294rl. I have 2 ac units, 1 in the living arear and the other in the bedroom. It has 2 airexcel thermostats, living room one is right before the hallway in the kitchen and the other is left wall right after the bedroom door.

Now it seems to be with both but they are always reading way cooler then room temp. Last night me and wife woke up sweating... temp set to 74,TS reading 74...turn it down to 70, ac kicks on we go back to bed. Wake up again hot as ca be... TS reading 70.. again I crank it down to 68... sleep and repeat wake up again room is warm TS reading 68.

Is my thermostat broken? Is there a external sensor mounted somewhere. Is it just mount in a bad location?

Again this happens for both ACs, ACs are also working just fine, I believe the issue is with the thermostats

[jsb5717]

Welcome to the forum! There's always a bit of a learning curve and troubleshooting when getting used to a new/different RV. It seems odd to me that both TStats would be faulty.

For starters I would get a simple stand-alone thermometer...maybe a couple of them...one for the bedroom and one for the living area. You would be able to see if your TStats are reading correctly or if you just need to dial it in differently. Ambient outdoor temp and humidity also play a part in sleeping comfort.

We like to sleep cool in our rig. At night I turn the TStat down to 64 degrees on AC setting.

[Daryles]

The Dometic Capacitive Touch (CT) thermostats has been problematic at best. Mine are about 4⁰F off. In the past if you call Dometic they would mail you new ones, no questions asked.
As mentioned above, get some remote thermometers. I bought this one
ORIA Indoor Outdoor Thermometer with 3 Wireless Sensors, Digital Hygrometer Thermometer, Temperature Humidity Monitor Meter with LCD Backlight, Wireless Thermometer for Home, Office, Bedroom, White https://a.co/d/5VcQt0m

I put one outside, one in the battery compartment (to monitor my lithium batteries) and one in the underbelly to keep an eye on temperatures down below in the winter.
I put it down the hole under the kitchen sink where the drain pipe goes to the galley tank. If you remove the panel under the sink you will see it.

[RMcNeal]

One thing I also found with the Dometic thermostats is that it is very sensitive to air blowing directly on it. Make sure you don't have a vent blowing at the thermostat. Mine in the kitchen is above the coffee bar and under a cabinet, so cold air would collect and circulate in that area. In the morning when I make coffee, the warm air from the coffee maker trapped under the cabinet would heat the thermostat and cause the air to kick on too soon. It's much better since I switched to the MicroAir thermostats.

[jimcol]

Not familiar with your thermostat, and this might be a long shot, but is it possible it is set for Celsius and not Fahrenheit?

[Lee-CI]

I believe you have a model 9630-3371 thermostat, though a photo would help to confirm.
Hold the Mode button (the long bar button vice the up / down arrows) 5 seconds to change from Celsius to Fahrenheit or vice versa.

AIRXCEL has a product help line at (574) 247-9235.

[Foldbak]

I have the same Coleman Maxair thermostats but Ive never verified the temp readings. I do know that get different temp readings in the two locations.



As far as being set to Celsius, I doubt it. 68 Fahrenheit is 154 Celsius . Like jeff said, use an external thermometer to verify.

[Fred]

I believe it may depend of what heat source you are using. The digital thermostats when in A/C or Heat-pump mode read the room temperature at the unit (i.e. at the ceiling return side of the unit) and when in gas furnace mode they read the temperature at the thermostat. This creates a large difference in the reading where the ceiling temps are going to be higher than at the thermostat. You can have a perfectly good thermostat but the thermistor sensor in the unit can be off.

[DutchmenSport]

Like other have stated already, pick up a stand along thermometer and place right beside the thermostat. Using the stand along thermometer, you'll be able to calibrate exactly where your comfort level is. Mine reads about 4-5 degrees warmer than what the actual temperature read out is on the stand along thermometer. So it's just a matter of setting the thermostat from 70 to 75, and then it's really 70 or 71 at that spot.

Another thing to remember, no two spots inside your camper will have the same temperature ... anywhere.

You can move that themometer 5 feet and have a couple degrees difference in temperature. Move it to the upper floor and you could have 5 - 7 degrees difference. Move it to the bathroom and it can be different, yet again. And the temperature near the floor is always colder than 5 feet higher (at your head level), and even warmer yet at the ceiling. From the floor to the ceiling in the same spot, you could have 8-9 degrees difference, depending on the outside ambient temperature.

The reason for this is simply because of the uneven heat through the camper caused by cold air coming in through drafts in the slides, the windows, the air conditioner vents in the winter and the return vent under the stairs in the summer. And remember, the ceiling vents for air conditioning and the floor vents for heat are not calibrated through the camper for steady heat or AC flow. The front ones may blow the strongest, the back ones the weakest. The kitchen are may blow nothing. The thermostat in the middle of the camper may be set on 70 and indeed in that space, it's reading 69 and the furnace is running attempting to bring it up to 70. But, because of the vent work in the camper, 75% of the air is actually blowing in your bedroom .... thus ... causing it to be extremely hot.

Pick the spot you want the temperature to be consistent for your comfort. That may just be your bedroom. Set the thermometer there and then adjust the furnace thermostat (or air conditioning thermostat) until you have the temperature you desire (for example in your bedroom). You may find there several degrees difference in what the two are showing!