Year's ago I had an outdoor boiler and am currently hooking one up again. I have everything hooked up but I'm stuck on how to wire in my second thermostat. What I have is a thermopride oil fired furnace with a heat exchanger in the plenum to transfer heat from the OWB. I want to retain use of the oil furnace (set at a lower temp) in case the OWB goes out. I want the second thermostat (set at a higher temp) to run the furnace fan to blow through the exchanger in the plenum. I had this set up on my last system but cat remember how to wire it. The second thermostat I'm using is a white Rogers 110v. Any help would be extremely appreciated.