My house is 3.5 years old in Moses Lake Wa. This problem just surfaced a few days ago with recent temps ranging from 10-45 degrees . With the thermostat set on heat, then the air "blows cold" from the ducts until the the temp drops a couple degrees and defaults to the aux. heat. The fan and furnace blower are working, but no heat. I set the thermostat to emergency heat and the furnace blows warm air. I reset all breakers and checked for loose wires. Is there anything else I should do before phoning for repairman? thermostat: Honeywell #T8011R 1016 Heat pump: Ducane HP 10B60 air handler: Ducane #DB60D