How much does it cost to fix Keston error code RED LOCKOUT BUTTON?

Typical repair cost for the Keston RED LOCKOUT BUTTON fault is £100-350 including labour.

RED LOCKOUT BUTTON High

Keston RED LOCKOUT BUTTON Fault Code

Q: What does the Keston RED LOCKOUT BUTTON fault code mean?

Your boiler has detected a safety or performance problem and has shut itself down to prevent damage.

Also written as REDLOCKOUTBUTTON — same fault.

The Keston RED LOCKOUT BUTTON fault code means: your boiler has detected a safety or performance problem and has shut itself down to prevent damage.. It appears on 1 Keston model in our database.

Technical description: Shut down signal / Red light on the instrument panel

Typical repair cost £100-350 (including labour)

DIY fix possible

Check that your gas supply is active and credit is on the meterEnsure the condensate drain pipe outside has not frozen in cold weatherPress and hold the red reset button for three seconds to restart the system

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Keston models that show the RED LOCKOUT BUTTON fault code

Click a model for the full fault code list and model-specific repair notes.

R-sm 20 FB Repair: £100-350

Source

Keston RED LOCKOUT BUTTON fault code information on this page is sourced and cross-checked against the official Keston service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026