I have a Trane Xl1200 Heat pump. It has been working fine since installed (2000), with no problems at all. As of this morning, the outside heatpump unit has stopped working. It will not start or turn on, even when I have the "heat" setting on the thermostat. The inside furnace fires up, and will heat the house in the "EM" emergency mode, but on regular "Heat" mode, there is just room-temp air being blown in because the outside unit won't turn on.
I know some basic electrical, but not much about HVAC units..
I checked the breaker to the outside unit, they are fine.
I checked the 2 20amp fuses in the box mounted near the outside unit, they are fine.
I verified that power is getting to the unit from both the main line and the thermostat wires.
There is a small circuit board inside the heatpump unit. It is about 4" x 6", says "Made by American Standard" on it. There is a small light with the word "Port" written below it, and small "lightning bolt" symbols next to it. The light is green, and it is steadily flashing. I have a feeling this is telling me something, but I don't know what it means...
Anyone have any ideas or suggestions?