Heat Pump Parts Names and Functions — Complete Guide
Published: July 22, 2026 — BC Wide Home Services Ltd, doing business as BC Wide Heating & Air Conditioning — Greater Vancouver, BC
Main Heat Pump Components
Compressor: pumps refrigerant through the system. Outdoor coil: absorbs or rejects heat (acts as evaporator or condenser). Indoor coil: releases or absorbs heat inside. Reversing valve: switches between heating and cooling modes. Expansion valve: regulates refrigerant flow. Fan motors: move air across coils. Capacitors: provide electrical boost to motors.
Control and Safety Components
Control board: manages all operations. Defrost board: controls the defrost cycle. Defrost sensor/thermostat: detects frost on the outdoor coil. Contactor: switches power to the compressor. High-pressure switch: shuts down system if pressure is too high. Low-pressure switch: shuts down if refrigerant is low. Thermistors: temperature sensors for various locations.
Line Set and Refrigerant Components
Line set: copper tubing carrying refrigerant between indoor and outdoor units. Insulation: foam covering on suction line. Service valves: allow connecting gauges for refrigerant service. Filter drier: captures moisture and debris. Accumulator: prevents liquid refrigerant from reaching the compressor. Refrigerant: the heat transfer medium (R-410A or R-32).