My house is using 2-stage heating. 1st stage is Radiant Heat (oil furnace). 2nd stage is Forced Hot Air (Unico system). I have 2 thermostats controlling the house (1 for upstairs, 1 for downstairs). My upstairs 1 is set for 2nd stage to come on 20 minutes after 1st. It seems that even after the room reaches temperature and the thermostat stops calling, the relay in my machine room doesn't turn off (which makes it continue to run). If I disconnect the relay wire for my 1st stage so I only use 2nd stage, it works fine (relay shuts off). What's also weird is that it seems if I set my 2nd stage to turn on in 5 minutes (instead of 15 or 20) it also works fine and shuts off. My HVAC guy tried a new thermostat and same problem exists. Also tried changing relay, with no luck. He is now telling me that he want to install 2 thermostats, 1 for radiant and 1 for Unico (which I don't want). Other people have suggested that it may be an issue with the wiring (pinched wire etc.). Help!