Ideal PCB Communication / Internal Lockout

Ideal boiler shows L9 and may intermittently stop and start

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

Internal PCB fault, Loose harness connections, Voltage spikes, Moisture on PCB

Safety first: Isolate power before any inspection. Do not remove the boiler case.

User steps:

Power reset: Turn off the boiler at the fused spur for 5 minutes, then turn back on.
Check environment: Ensure the boiler cupboard is dry and well ventilated. High humidity can contribute to PCB issues.

If L9 persists or recurs, a Gas Safe engineer should inspect and likely replace the PCB after checking for underlying causes such as leaks.

Professional Required 5/5

PCB (Printed Circuit Board)

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