Sime Intermittent Lockout

Boiler frequently locks out and needs manual resetting, with varying or no error codes

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Unstable gas supply, Intermittent PCB fault, Loose electrical connections, Overheating due to partial blockage

Safety first: Do not repeatedly reset a boiler that locks out; this can mask a serious fault.

Note conditions: Record when lockouts occur (e.g., during DHW use, in windy weather, or at peak gas times) to help diagnosis.
Check ventilation and flue terminal: Ensure adequate air supply and a clear flue terminal.
Engineer inspection: A technician should check gas pressures, electrical connections, PCB, sensors, and system cleanliness. Any intermittent component should be replaced.

Hard 4/5

Main Control PCB

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