Air Source Heat Pump Repair
in Basingstoke & Hampshire

Your heat pump diagnosed and repaired by a specialist — not a generalist. We find the actual fault, fix it properly, and get your system back to full performance.

Over 500 heat pump systems diagnosed and repaired across Hampshire. Average response time under 4 hours.

Air source heat pump repair covers the diagnosis and correction of faults affecting heating output, hot water production, efficiency, and system reliability. Whether your system has stopped working entirely, is producing error codes, or is simply not heating your home as it should, this service identifies exactly what is wrong and fixes it.

This service is for homeowners and businesses with existing air source heat pump installations that are underperforming, making unusual noises, cycling incorrectly, or failing to reach target temperatures. It applies to all major brands including Mitsubishi, Daikin, Samsung, Vaillant, Grant, and Panasonic.

Professional repair matters because heat pumps are complex systems involving refrigerant circuits, electronic controls, flow rates, and pressure differentials. A misdiagnosis leads to wasted money on parts that were never the problem. Craig Ball has spent over 15 years working exclusively with these systems, starting in commercial heating and ventilation before specialising in heat pump fault finding.

We serve domestic and commercial properties across Basingstoke, Hampshire, Berkshire, Surrey, and Wiltshire. Every repair comes with a clear explanation of what we found, what we fixed, and what to watch for going forward.

A heat pump that is not working correctly does not just cause discomfort — it costs you money every hour it runs inefficiently. Systems drawing full electrical input while delivering reduced heat output can increase your energy bills by 30–50% without any visible sign of failure.

Ignoring early warning signs — such as short cycling, unusual compressor noise, or fluctuating flow temperatures — often leads to secondary component damage. A faulty expansion valve left unchecked can damage the compressor, turning a £300 repair into a £2,500 replacement.

Many homeowners call a general plumber or heating engineer first. Without specific heat pump training, these engineers often reset the system, clear an error code, and leave — only for the fault to return within days. This wastes your time and delays proper diagnosis.

In colder months, a broken heat pump means no heating and no hot water. Waiting for a non-specialist to attempt multiple visits while your family goes without is avoidable. A specialist resolves the root cause on the first visit in the majority of cases.

Air source heat pumps operate on a vapour compression cycle, extracting low-grade heat from ambient air and upgrading it to usable temperatures via a refrigerant circuit. Faults can occur in any part of this cycle — from the evaporator coil and fan assembly to the compressor, expansion valve, four-way valve, and condenser.

Common faults we diagnose include low refrigerant charge (often indicating a leak), blocked or dirty evaporator coils reducing airflow, failed or sticking expansion valves causing superheat or subcooling issues, compressor electrical faults, PCB controller failures, and incorrect installer settings that cause the system to operate outside its design parameters.

We work with monobloc and split systems. Monobloc units house the entire refrigerant circuit outdoors, with water connections running into the property. Split systems have refrigerant pipework between indoor and outdoor units. Each type has different failure modes and diagnostic approaches.

For systems using R410A, R32, or R290 refrigerants, all work is carried out in compliance with F-Gas regulations. We hold the appropriate certifications for handling, recovering, and recharging refrigerants. Leak testing is performed using electronic detectors and, where necessary, nitrogen pressure testing.

We also address system-level issues that are often misdiagnosed as heat pump faults — such as incorrect buffer tank sizing, poorly configured weather compensation curves, inadequate emitter sizing (radiators or underfloor heating circuits too small for the design flow temperature), and hydraulic issues including air locks and incorrect pump speeds.

Residential repairs typically involve single-phase units rated between 5kW and 16kW. Commercial systems may be three-phase, larger capacity, and operate in cascade configurations. We are experienced with both and carry appropriate testing equipment for each.