I recently replaced a an older (~25 year old) Trane Geothermal unit due to freon leaks. I opted to re-use the aux emergency heater from the old installation since it was like new (never been on). Anyway, the system I installed is the Trane T1GX series, which I soon found out is made by WaterFurnance, and has the Premier Control Board. The question I have is on the wiring for the EM heat. It appears the Premier board has 4 stages of EM heat. I have only 1, and want to connect it to the control board. Rather than test the individuals wires that control the EM heat and figure it out, does anyone know which wire color is for Stage 1? Stage 2? Stage 3 Stage 4? By looking at the schematic, I appears that Orange, Blue, Pink and white are the 4 stages. Also, does the control board source the 24vac or sink (provide a ground)?