Bernie, It sounds like you may have a short in the low voltage wiring on the thermostat side. You would want to disconnect the thermostat wires and power the board up to see if it remains energized. If it does you will need to locate and repair the shorted wiring.
Bernie, It sounds like you may have a short in the low voltage wiring on the thermostat side. You would want to disconnect the thermostat wires and power the board up to see if it remains energized. If it does you will need to locate and repair the shorted wiring.