BoilerFaultCodesWhat the manual says
Manufacturer manualHeating mode: Frost protection (Frost protection mode active)
What causes this fault?
This occurs when the boiler's internal sensors detect that the water temperature has dropped below 5°C. To prevent the unit from freezing and potentially bursting a pipe, the boiler automatically fires up the burner and runs the pump until the water reaches a safer temperature. This is a normal safety feature designed to protect your heating system during extreme cold spells.
This status code is almost exclusively seen during the winter months when external temperatures drop below freezing.
DIY fix possible
No action is required; this is a normal safety function.The boiler will stop this mode automatically once the internal water temperature rises sufficiently.Ensure your external condensate pipe is not frozen if the weather is extremely cold.
Avoid the next call-out bill
A cover plan would handle faults like S.34: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.