E12 High
Your boiler has detected that water is not circulating correctly through the system, preventing it from heating up safely.
Technical description: Differential water flow switch fault (still open).
Typical repair cost: £120-280 (including labour)
DIY fix possible
Check that your boiler pressure is between 1.0 and 1.5 bar on the gaugeEnsure all radiator valves and isolation valves under the boiler are fully openBleed your radiators to remove any trapped air pocketsReset the boiler by turning the selector switch to 'R' for five seconds
Protect yourself from future repair bills
A boiler cover plan would cover faults like E12 — no call-out fees, no surprises.
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Parts commonly replaced
- Circulation Pump
- Water Pressure Sensor
- Flow Switch
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