BoilerFaultCodesYour heat pump has stopped working because of a communication or electrical fault in the main power control unit.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Inverter Error
What causes this fault?
This fault occurs when the internal brain of the heat pump loses the ability to manage the power sent to the compressor. It is usually caused by a failure in the electrical components that convert power, or a breakdown in communication between the main control boards. Effectively, the system can no longer safely regulate the energy needed to run the outdoor unit.
This error is more frequently seen during peak summer or winter months when the heat pump is working hardest and electrical components are under the most thermal stress.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like LC5 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
Affiliate links — we may earn a commission at no extra cost to you.