I have two zones furnace, one control first floor with thermostat in the living room and the second control second floor with thermostat in the Bedroom. I won't get heat second floor unless downstairs thermostat is set high 'on'. if first floor thermostat is off 'set low' and second floor one is on the second floor grill won't heat up unless if I turn first floor on....eventhough the Heat pipes in the furnace room going up is Hot.
first floor heat start just fine. if I turn first floor thermostat off I won't get heat second floor even though the thermostat second floor is set to high temp..
Second floor Heat totaly depend on first floor Heat. I'm woundering if the wiring is connected right or the thermostat in the second floor is not functioning right.