Heat Pump Annual Service Checklist: What Should Be Done

Why Annual Servicing Matters

Annual servicing is the single most important maintenance task for a heat pump. It maintains efficiency, extends system life, keeps your warranty valid, and catches developing faults before they become expensive repairs. A well-serviced heat pump can maintain its original CoP for 15–20 years.

Outdoor Unit Checks

• Visual inspection for physical damage, corrosion, or weathering
• Clean or flush the evaporator coil (removing dirt, leaves, and debris)
• Check fan blades for damage or wear
• Test fan motor speed and current draw
• Inspect refrigerant pipework and insulation for damage
• Check anti-vibration mounts and fixings
• Test defrost sensor and control operation

Refrigerant Circuit Checks

• Check refrigerant pressures (suction and discharge)
• Calculate superheat and subcooling
• Inspect all connections for signs of refrigerant leak
• Check compressor operation and current draw
• Inspect expansion valve operation

Indoor Unit / Hydrobox Checks

• Inspect and clean air filters (if applicable)
• Check heat exchanger for scaling
• Verify flow and return temperatures
• Check system pressure and top up if required
• Inspect pump operation
• Check and test all sensors

Controls & Electrical

• Check all electrical connections for tightness and corrosion
• Test safety devices (high-pressure cut-out, low-pressure cut-out)
• Verify controller settings and update firmware if applicable
• Test weather compensation curve settings

Hot Water Cylinder (if applicable)

• Check cylinder temperature settings
• Verify legionella prevention cycle is set correctly
• Inspect immersion heater operation
• Check expansion vessel pressure