Model # could be 1F80-240 or 224. Cooling works fine, but no heat. Consulted R-W online info and tried overriding the program by selecting'heat,'pressing 'hold' 5 seconds, used up/down buttons to select temp. No luck. Also tried selecting a temporary hold time of 6 hours and then requesting a temp more than 3 degrees higher than current temp... no luck. I am a tenant not an owner. Help, it's cold. The fuse is not blown.