S.34 High
Your boiler has paused operation because it believes the internal temperature is so low that the pipes are at risk of freezing.
Technical description: Heating mode frost protection error
Typical repair cost: £90-180 (including labour)
DIY fix possible
Check that the room thermostat and radiator valves are turned upEnsure the boiler's power supply is constant and has not been switched offIf the condensate pipe is outside, check if it is frozen and gently thaw it with warm waterWait 15-30 minutes for the boiler to warm up naturally before resetting
Protect yourself from future repair bills
A boiler cover plan would cover faults like S.34 — no call-out fees, no surprises.
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Parts commonly replaced
- NTC Temperature Sensor
- Condensate Trace Heater
- PCB
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