Dometic furnace pulsing on and off
We went away from coach for the afternoon and while gone there was a hard driving rain (nearly sideways) and brief power outage. When we came into coach the furnace fan was cycling on and off about every second. Thermostat was set for AC. Turning off thermostat did nothing. Threw salesman switch and it stopped. Turned salesman switch back on and started pulsing again. Finally pulled 20 amp 12v fuse to stop it. Reinstalled fuse and pulsing started again. Pulled fuse again to make it stop.
Our 40,000 BTU furnace was replaced with a new Dometic after the original Atwood Excalibur went out in the great Texas Freeze in February 2021. Bad heat exchanger and burner.
An internet search found a couple of people with newer travel trailers experiencing the same symptom. They tracked it down to moisture in area of control board. After drying connections and the board their symptoms went away. Opened up my furnace the next afternoon and it was dry. Performed fine when tested.
This is my first go round with this problem, hopefully last. My unit seemed well sealed but a Texas toad strangler is a thing unto itself.
Topic: Dometic furnace pulsing on and off