Even tho you state you ARE selecting Gas heat, is it possible you are possibly selecting HP on 1 zone? The RVP system has a 5 degree separation when on HP. If you have it on HP mode(either zone) it will revert to Furnace IF THE TEMP SELECT IS MORE THAN 5 DEGREES. So, 74 on stat. You select 68, the furnace clicks which it should NOT. But the 68 is out of the 5 degree and will cause furnace operation. BUT your setting is calling for HEAT, NOT COLD. I could see a possible conflict if it was 68 in the RV and you set for 74. So, I have another question. You select GAS Heat. The interior of the RV per the Tstat is 74. You are setting the Furnace at 68 because you want to make sure the RV, NEVER gets below 68 degrees? But the furnace still clicks? I would take a can of compressed air and blow out the wall tstat circuit board. Also, loosen the remote temp thermisters in the ceiling/wall mount screws. Doug