High
Red LED is 'ON' on Potterton Kingfisher MF RSL/CFL

Your boiler has detected an internal fault or is not receiving a signal to start, and has locked itself out for safety.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

What the manual says

Manufacturer manual

Boiler fails to work (checks required: Electrical Plugs PL1 to PL6, External Call for Heat, Boiler Temperature Knob, Gas & Water Connections, Main Supply Voltage).

From this model's manual
Verified against the Potterton Boiler Kingfisher Mf Rsl And Cfl installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the boiler's internal computer stops the system because it hasn't received the correct electrical signal to start or has detected a failure in the ignition sequence. The most common reasons include a lack of communication from your wall thermostat, a failure in the electronic control board, or a component like the gas valve not opening to allow the flame to light.

This fault is often seen during the first cold snap of autumn when external thermostats are turned up for the first time and older electronic components struggle to handle the sudden demand.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Avoid the next call-out bill

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