Troubleshooting A Furrion AC System That Isn't Properly Communicating With A Furnace

Updated 12/02/2025 | Published 11/10/2023

Products Featured in This Question

Replacement Premium Wall Thermostat for Furrion Chill HE RV Air Conditioner - Single Zone - Black

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$90.95

Replacement Premium Wall Thermostat for Furrion Chill HE RV Air Conditioner - Multi Zone - Black

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$95.37

Question:

I have a new forest river travel trailer with a Furrion thermostat .... When I am using it in the furnace mode, I have to set it 10 degrees more than what I want it to come up to. Is there a fix for this?

asked by: Cliff R

Expert Reply:

Depending on the model you have the temperature probe for your system could be up in the air distribution box and since heat rises the air up by it could be warmer and preventing the system from coming on, causing you to set it 10 degrees more than needed. Newer Chill HE thermostats have the temperature probe inside of them instead for a more accurate reading. If you have a single zone (one AC unit) you'll need part # FR33PR and for a multi-zone (multiple AC units) you'll need part # FR93PR.

I've asked Furrion in the past and they've stated that the probe inside of these newer thermostats would override the one built into the zone controller so you shouldn't have to do anything extra in order to correct this problem.

expert reply by: Kevin C

Mary

11/25/2024

I need help with a furrion thermostat in a 2025 Cardinal Forest river fifth wheel

Kevin C.

11/26/2024

@Mary Are you getting an error code or is there some other issue going on?

Mary

11/26/2024

@KevinC there code on the thermostat is E 3 it goes off and then comes back on

Kevin C.

11/26/2024

@Mary An E3 error code means the thermostat and controller in the air distribution box are losing connection and can't communicate. I would disconnect your RV from shore power and disconnect the batteries to completely cut power to the AC system and wait for 15 minutes for any power still in the wires to dissipate. Typically a full reset will clear this error but there could be something else causing this. If so, I would remove the thermostat from the wall mount and check the wires on the back. Some times the "A" and "B" communication wires that run between the thermostat and controller are installed backwards the RV manufacturer so I would check them at the controller and thermostat to make sure "A" and "B" are both running to the correct ports. You can also check for any loose or damaged wires during this. The next thing to check would be whether the thermostat is getting a full 12 volts or if it's dipping below 12 volts. Using a multimeter # PT89ZR you can test the power wire running to the thermostat. I've had others in past have power issues with the RV that caused a frequent dip in voltage which would cause the thermostat to stop functioning correctly and communicating with the controller. If you feel like you're experiencing voltage drops you can use a meter # HU28FR that just plugs into an outlet. He has a light up screen that will turn red any time the voltage drops below 108v or rises to 132v. It's a bit easier to catch a voltage drop with one of these rather than having to sit at an outlet with a multimeter waiting for it to happen.