Flow return reversed High
Your boiler has detected that hot water is moving in the wrong direction or through the wrong pipe, which is preventing it from heating your home safely.
Technical description: Check if the flow thermistor is correctly clipped to pipe. If not, replace flow thermistor.
Typical repair cost: £100-220 (including labour)
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Protect yourself from future repair bills
A boiler cover plan would cover faults like Flow return reversed — no call-out fees, no surprises.
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Parts commonly replaced
- Flow thermistor
- Return thermistor
- NTC sensor clip
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