Will The Coleman-Mach Single Zone Digital Thermostat CM76RR Power The AC And Suburban Heater?

Published 09/29/2026

Question:

I have a Coleman Mach 10 rooftop air conditioner paired with a Airexcel 9420A3382 Thermostat. The cooling side works, but the heat side does not work. The heater furnace is Suburban SF 25FQ. I am under the impression than when the RV a/c was upgraded, the thermostat was the factory install. Is the CM76RR the recommended replacement?

asked by: Michael F

Expert Reply:

Hi Michael!

The Coleman-Mach Single Zone Digital Thermostat # CM76RR is indeed the manufacturer-approved replacement for your 9430A3382 thermostat. It will control both your Coleman Mach 10 AC and Suburban SF-25FQ furnace. Before replacing the thermostat though, it wouldn't hurt to check the following issues (they are fairly common with this set up):

-Dip switches: Make sure the thermostat is set for Gas Furnace, not Heat Pump or Heat Strip.
-Fan setting: Set the fan to AUTO when using the furnace.
-Furnace wire: Check that the furnace signal wire (usually white) wasn’t disconnected when the new A/C was installed.

If you do end up replacing the thermostat, make sure to shut off the RV’s 12V HVAC/furnace power first and configure the new thermostat for Gas Furnace / Single-Stage Cool.

Out of curiosity, do you hear a faint click behind the wall thermostat when you turn the heat on? And does the furnace blower motor turn on at all, or is it completely silent?

expert reply by: Lazer S