1021 B High
Your boiler is unable to provide hot water because it cannot accurately measure how hot the water is.
Technical description: Hot water temperature sensor is defective – the plug to the hot water temperature sensor may not be connected
Typical repair cost: £90-160 (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 1021 B — no call-out fees, no surprises.
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Parts commonly replaced
- Domestic Hot Water (DHW) Temperature Sensor
- Wiring harness connector
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