What does an air source heat pump service include?

An air source heat pump service combines a condition check, safety inspection, cleaning and operating tests. We examine the parts that affect heating output, electricity use and reliability, then explain anything that needs attention.

Outdoor unit

Leaves, dust and other debris can restrict airflow through the coil. We inspect and clean the coil where needed, check the fan and guard, and look for damage, corrosion or unusual vibration. We also check that air can move freely around the unit and that nothing has been stored too close to it.

Blocked drainage can allow defrost water to freeze around the base. We check the condensate route, tray and discharge point, particularly where frost or poor ground drainage could cause a problem. We inspect the pipe insulation and external covers for damage or gaps.

Water circuit and heating equipment

Low pressure, trapped air or restricted flow can leave some rooms cooler than others. We check system pressure, valves, pumps, strainers and filters, along with the expansion vessel where it forms part of the system. We look for leaks around joints, cylinders, buffer tanks and other accessible components.

If the property has older radiators or underfloor heating, we check how the emitters are responding to the heat pump’s lower flow temperatures. We can identify balancing problems, cold spots or controls that prevent the system from delivering heat properly. A service will show where a separate alteration may be worthwhile; it does not automatically include changing radiators or pipework.

Controls and electrical safety

Incorrect settings can make a heat pump run for longer than necessary or fail to maintain the intended temperature. We review the programmer, room controls, thermostats, weather compensation and heating schedule. We check that heating and hot water settings match how the property is used.

At the electrical side, we inspect accessible connections, isolation points and protective devices for signs of overheating, damage or looseness. We also review fault records and warning messages where the controls provide them. This helps distinguish a settings issue from a fault that needs further investigation.

Operating tests

A system that starts normally can still be underperforming. We run the heat pump and observe its heating and hot water operation, including circulation, temperature changes, defrost behaviour and compressor operation. We compare the readings with the system’s expected operation and investigate abnormal noise, cycling or temperature differences.

These tests help us identify issues such as restricted water flow, poor sensor readings, control faults or a developing component problem. If the refrigerant circuit shows signs of a fault, we explain the next step and arrange the appropriate investigation rather than treating the symptom as a routine adjustment.

What happens after the service

At the end of the visit, we explain what we found in plain terms. You receive advice on any minor maintenance, settings changes or monitoring that could help prevent a repeat problem. If the system needs repair or further work, we separate that from the service and provide a written quotation before proceeding, so the decision and cost are clear.

Servicing does not replace a full heat pump survey or redesign. If the issue relates to insulation, radiator sizing, pipework or the way the system was installed, we explain that distinction and recommend only the investigation needed to establish the cause.