Our 5er has 2 AC units and one furnace. It also has one Dometic thermostat that operates two zones or areas in the trailer. Zone one is the bedroom. Zone two is the living area. To set the thermostat, step one is to select the zone, then select AC, furnace, fan only, fan speed or off. Then set the desired temperature. Zone two is the living area. Use same technique to set thermostat.
We should be able to set zone two to furnace only and heat should come out of appropriate vents in the living area. What actually happens is heat comes out of vents in bedroom and bathroom, but NONE comes out of the vents in the living area. And the AC unit in the living area comes on, which should not happen.