BoilerFaultCodesYour heat pump’s internal power control system has encountered a fault, meaning the outdoor unit cannot currently run to provide heating or hot water.
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 power management system, known as the inverter, stops communicating correctly with the main computer of the heat pump. The most common reason is an electrical failure within the inverter circuit board due to power surges or component wear, which prevents the unit from controlling the fan and compressor speed.
This fault can be more frequent during summer or extreme heatwaves, as high ambient temperatures put additional thermal stress on the electronic power components.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A boiler cover plan would cover faults like J46 — no call-out fees, no surprises.
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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.
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