H.01 – .18 High
Your boiler has stopped working because water is not moving through the system properly or a temperature sensor has detected an overheating issue.
Technical description: No water circulation, insufficient circulation or sensor error.
Typical repair cost: £120-£350 (including labour)
DIY fix possible
Check that your boiler pressure is between 1.0 and 1.5 bar on the internal gauge.Ensure all radiator valves and any isolation valves under the boiler are fully open.Attempt to reset the boiler by turning the selector switch to the reset position for five seconds.Bleed your radiators to remove any trapped air that may be blocking circulation.
Protect yourself from future repair bills
A boiler cover plan would cover faults like H.01 – .18 — no call-out fees, no surprises.
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Parts commonly replaced
- Central heating pump
- Temperature sensors (NTC thermistors)
- Main heat exchanger (flushing/cleaning)
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