High Lockout
Fault 20 / 193 on Worcester Bosch Greenstar CDi Compact

Your boiler's computer and its remote control are having trouble speaking the same language, causing the system to stop working correctly.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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.

Technical description

System configuration: invalid. Invalid coding in remote control for the heating circuit.

What causes this fault?

This fault occurs when the boiler's internal computer receives conflicting information about how it should be operating. The most common reason is that a newly installed part or external thermostat hasn't been programmed correctly to talk to the boiler, or an electrical glitch has corrupted the system's memory. It essentially means the boiler has forgotten its own identity and shuts down as a safety precaution.

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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