I've got a Trane YCC42F Combination Cooling/Gas Heat HVAC unit. Worked fine all last winter (my first winter in this home) and this winter up until last night. We woke this morning to a heater blowing cold air and a house in the mid-50's degrees.
The unit is located on my roof. I turned off the thermostat in the house, went up, opened the unit, and had my wife turn the heat on while I was at the unit.
The fan comes on, but I get no other action. No gas flow, no electric ignitor clicking, no flames.
Is there a simple solution to this or do I need to call a tech?