QUOTE(pianotuna @ Aug 10 2009, 09:56 PM)
I can't use one thermostat because the selection setting switch is furnace, airconditioner, off, and heat strip. It can't be in two positions at once.
I want to be able to use both to increase the speed at which I can warm up the RV--and also to have the heat strip carry as much of the load as possible--setting the furnace to cut in a degree or two colder than the heat strip setting.
I think you answered your own question when you said you wanted the heat strip to carry a load different from the furnace.
The only way you can do that is with two thermostats. However, if you are looking for a 2 stage system, that is possible with a 2 stage heat cool thermostat, but you might need to run some additional wiring depending on what is in the back of the existing thermostat hookup. Most heat pump thermostats are 2 stage heat, one stage cool, and are available from home depot.
Run the w1 terminal to the furnace along with a ground wire. Run W2 to the heat strip contactor, and the y1 to the cooling contactor on the A/C. Run the G to the fan contactor. The R terminal is for the transformer or control voltage input.
You will not need the Orange or blue which go to the reversing valve in two types of wiring scenarios.