Secondary thermostat sensor

[JVfromGrnBay]

We are having an issue with the thermostat when using our heat exchanger, and I understand there may be a secondary temperature sensor that is at fault. When no heat is turned on, the thermostat on the wall reads the indoor temperature. However, when the heat exchanger is turned on, the reading is no longer accurate, and has been significantly lower than the interior temp, causing the heat pump to run continuously. We have achieved indoor temps near 80 degrees, yet the thermostat still indicates a temp in the low 50's. I have heard there may be a secondary temp probe in the return air plenum that needs to be disconnected. Can anyone confirm this, and help me to identify the connection? Is it the connection indicated by my finger in the attached photo? We have a 2021 GT 25, FTB with one A/C unit

[Spartanguy]

Your roof sensor is probably in the drain duct: https://www.airforums.com/forums/f42...em-203350.html

[Spartanguy]

I hate that that photo shows up, someone posted a close but unrelated photo there and it confusingly dominates the thread cover (we don’t have anything that looks like that plastic pool drain on our Airstreams), if you look inside that link you’ll see some good photos and people explaining where that other “sensor” is.

I am so suspicious of that problem, I think every Airstream since at least 2015 is coming out of the factory with that quality control issue.

[WoodGrain]

We had a similar problem with our 2018 27FB Globetrotter. Our trailer has 1 A/C unit.

A remote temperature sensor was wrongly installed in our trailer. There was no room cut-out for the sensor and cap and so we had no idea it was there. This sensor was picking up the temperature between the wall and fridge and using this reading to control the system.

A mechanic at Bill Thomas RV discovered the remote sensor and simply unplugged it. The sensor connection is in the ceiling above the return air grills.

This remote sensor is a white cable with a plug end. Google Dometic 3106486008 remote sensor kit for a picture of the cable end.

I don't have access to the trailer or I'd send you a picture of our installation, however you should be able to figure out if you've disconnected the remote sensor. If a remote sensor is installed and the system is on, the INSIDE TEMP displays the reading at the remote sensor. If off, the thermostat will display the temperature at the thermostat. If no remote sensor is installed, the INSIDE TEMP will display the same value whether on or off.

[Spartanguy]

[JVfromGrnBay]

Thanks for all the help on this. I finally got back to the trailer to test my fix and concluded that all is working well now. Here is the advice I found on the AA FB page that was the easiest fix, as I was unable to find the actual sensor:

Turn off your system. Take both your intake duct covers off (that’s the two rectangle filter covers on the ceiling) once they are off, there are a bunch of wires in white clips towards the back of the duct. You will find a small white cable with two wires in it which ends at a little white plug with a tiny red and white wires and another white cable exiting the little white plug. That’s the indoor sensor. Just unplug that. It basically makes your thermostat your indoor sensor.

[ebarthelme]

Omg thank you. You saved me. We are I. The desert and it keeps reading 51 degrees in zone 2. Found the wire and unplugged. Now Ac running.