Enhanced heat pump defrost without use of auxiliary heat

A device for controlling a heat pump system, the device comprising at least one processor coupled to memory, the at least one processor configured to:

• identify a signal received from a second device associated with an outdoor portion of the heat pump system, the signal indicating that the heat pump system is performing a defrost operation;
• reduce, based on the defrost operation, a speed of a fan associated with an indoor portion of the heat pump system;
• identify pressure data received from a pressure sensor during the defrost operation, the pressure data indicative of a suction line pressure of the heat pump system;
• determine, based on the pressure data, that the suction line pressure is below a threshold pressure during the defrost operation, the threshold pressure greater than a low-pressure fault threshold;
• and
• increase the speed of the fan based on the determination that the suction line pressure is below the threshold pressure during the defrost operation.

A system for controlling a heat pump system, the system comprising:

• an outdoor portion;
• an indoor portion;
• and
• at least one processor coupled to memory, the at least one processor configured to:
• identify a signal received from a second device associated with the outdoor portion of the heat pump system, the signal indicating that the heat pump system is performing a defrost operation;
• reduce, based on the defrost operation, a speed of a fan associated with the indoor portion;
• identify pressure data received from a pressure sensor during the defrost operation, the pressure data indicative of a suction line pressure of the heat pump system;
• determine, based on the pressure data, that the suction line pressure is below a threshold pressure during the defrost operation, the threshold pressure greater than a low-pressure fault threshold;
• and
• increase the speed of the fan based on the determination that the suction line pressure is below the threshold pressure during the defrost operation.