Low
Red LED two flash sequence on Worcester Bosch Greenstar CDi Compact

Your boiler has been manually set to run at its lowest possible power level, usually because a technician is performing a service or safety check.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

Service mode: Boiler is operating at minimum output.

From this model's manual
Verified against the Greenstar 27 30 RiCompact ErP 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.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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