BoilerFaultCodesWhat the manual says
Manufacturer manualSensor error: Bad connection to flow or return temperature sensor, Fault with flow or return temperature sensor(s), Low or no flow through boiler, Reverse flow through boiler
Shared across the 600 Heat range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Related fault codes
All 18 fault codes on the 600 Heat
Seeing a different code? Every code this model can display, in one place.