BoilerFaultCodesYour boiler is not reacting when you turn on the heating because it isn't receiving the correct signal to start that specific mode.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: No red light (other lights function in other modes) - CH Mode
What causes this fault?
This fault occurs when the boiler fails to receive the electrical signal telling it to provide central heating, even though the hot water might still be working. The most common reason is a communication failure from your external room thermostat or a worn-out internal switch that is responsible for toggling the boiler into heating mode.
This issue is most frequently noticed during the first cold spell of autumn when homeowners attempt to switch their heating on for the first time after the summer break.
DIY fix possible
Check that the room thermostat is turned up higher than the current room temperature.Ensure the mechanical clock or digital programmer is set to 'ON' or 'AUTO'.Replace the batteries in your wireless room thermostat if it has them.
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A boiler cover plan would cover faults like FAIL POINT D — no call-out fees, no surprises.
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Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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