In cooling mode operation, which component is energized first?

In cooling mode operation of an air-to-air heat pump, the indoor fan is typically energized first. This is crucial because the indoor fan needs to circulate the air through the indoor coil to ensure that the cooling effect can be felt in the space being conditioned. When the thermostat calls for cooling, activating the indoor fan first allows it to begin moving air as soon as cooling is established.

Once the indoor fan is running, the compressor can be energized to start the refrigeration cycle. The compressor pumps refrigerant through the system, which absorbs heat from the indoor air. The expansion device works to control the flow of refrigerant into the indoor coil, and the outdoor coil dissipates heat outdoors. Energizing the fan first ensures that when the cool air is produced, it can be distributed effectively throughout the space, providing immediate comfort to the occupants.

Therefore, initiating the indoor fan at the beginning of the cooling cycle is essential for efficient operation and comfort.