101 High
Your boiler has switched itself off because it has become too hot internally, usually due to a lack of water flow or a blockage.
Technical description: Overheat error
Typical repair cost: £120-350 (including labour)
DIY fix possible
Check that your system pressure is between 1.0 and 1.5 bar on the pressure gauge.Ensure all radiator valves are fully open to allow water to circulate.Turn the boiler off and on again to see if the fault clears after cooling down.
Protect yourself from future repair bills
A boiler cover plan would cover faults like 101 — no call-out fees, no surprises.
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Parts commonly replaced
- Circulation pump
- Overheat thermostat
- Main heat exchanger (flushing/cleaning)
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