I recently bought a 1986 31' Sovereign
. I have been camping a few times. Of course I have given the A/C a good workout, but just recently noticed that there appears to be no heater! Other than a heat setting on the Coleman roof A/C, there is nothing that I can find. The owner's manual briefly refers to an "optional" furnace. I find it hard to believe a 31' Airstream would not have a heater. . ?????