Furnace Shutting Down - New Legacy 3121rl

[USA-C2C]

Sold our Airstream and bought a Montana Legacy 3121rl. New to 5th wheeling. Just took delivery after waiting for parts and dealer to fix bedroom slide (another day, another story).

Although I am plugged into 50 amp source at home, I set the HVAC IN-Command setting on rear A/C and chose Heat mode with gas source and fan off. I believe the furnace only runs off gas but the heat pump on the AC runs of electric.

The RV was cold, probably around 50 degrees, so I thought I was setting the thermostat to call for heat until the temp reached about 87 degrees (wanted it high to warm it up and test the furnace). See picture

The furnace engaged and started heating but after about 10 minutes it stopped. No other fan, or vent was running and the fireplace was also off.

I reset the rear AC to off, waited a minute or two, and then set it again to heat mode, gas, fan off and the furnace engaged again and starting hearting but then stopped again after about 10 minutes. Repeated the same procedure a third time and again the same results.

Not sure if I am doing something wrong or if I have a furnace problem. Any ideas are welcome. Obviously, I am testing many things and I have a list for the dealer.