The compressor is the most critical component in an air source heat pump, responsible for heat transfer and system efficiency. Common issues include noise, overheating, refrigerant imbalance, and electrical faults. In the UK, repair costs range from £800 to £2,500+, while replacement can exceed £3,500. Early diagnostics prevent major system failure and reduce long-term costs.

Air source heat pump fault finding is the process of diagnosing system issues such as water flow errors, refrigerant leaks, compressor faults, sensor failures, and electrical problems. In the UK, most faults can be identified and resolved with professional diagnostics costing £100–£800+, helping restore efficiency and prevent costly system damage.

A water flow error in an air source heat pump can reduce heating efficiency, increase electricity bills, and cause repeated system shutdowns if left unresolved. This guide explains the main causes of water flow faults, including low system pressure, blocked filters, circulation pump failure, airlocks, and frozen pipework. Learn how to identify warning signs early, understand repair costs in the UK for 2026, and know when repair or replacement is the better option.