High
FAIL POINT I on Worcester Bosch 24/28CDi II RSF

Your boiler has detected a problem with one of its internal temperature sensors and has stopped working as a safety precaution.

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.

What the manual says

Manufacturer manual

Flashing fast (Sensor Fault)

From this model's manual
Verified against the Worcester Bosch 24 28cdi Ii Rsf 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 control board loses communication with the temperature sensors or receives a reading that is outside of its safe operating range. The most common reason is that the internal thermistors have physically degraded over time or a wire has shaken loose, preventing the boiler from knowing if the water is becoming dangerously hot.

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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