When replacing a single pole compressor contactor with a double pole, how should you connect an off-cycle self-regulating crankcase heater?

Connecting an off-cycle self-regulating crankcase heater when replacing a single pole compressor contactor with a double pole is critical for ensuring proper operation and safety of the system. The correct approach is to connect one wire to the line side of one pole and the other wire to the load side of the same pole.

This configuration ensures that the crankcase heater is energized only when the compressor contactor is closed, allowing the heater to function during the off-cycle of the compressor. By connecting one wire to the line side (incoming power) and the other to the load side (outgoing to the heater), you achieve control over the heater's operation based on the contactor's state. This is essential, as it prevents the heater from running continuously when the compressor isn't operational, which can lead to unnecessary energy consumption and potential overheating.

In contrast, connecting both wires to the line side would keep the heater continuously energized regardless of the contactor position, which is not ideal for off-cycle operation. Connecting both wires to the load side would create an open circuit when the contactor is off, preventing the heater from functioning at all. Bypassing the contactor entirely would eliminate control, likely leading to improper heater operation and possible system damage or inefficiency.