Main floor heat not working
I've got a 2 story house, a thermostat on each floor (both appear to be working and batteries good). However, though I have my heat set to 68 on the main floor, it remains cold (62) and no heat seems to be coming from the registers. I turned on my second floor heat and it works fine. We have a single HVAC unit for both floors, so I'm not sure how this is possible. Any help/suggestions would be very welcome.