Low
C4-273 on Worcester Bosch Greenstar 28CDi Compact ErP

Your boiler has detected airflow when the fan should not have been running, which usually points to a temporary blockage or a sensor reading error.

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

Airflow present during last 24 hours

From this model's manual
Verified against the Worcester Bosch/Worcester Bosch Greenstar Cdi Compact 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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Related fault codes

C4View →EAView →D1View →

All 100 fault codes on the Greenstar 28CDi Compact ErP

Seeing a different code? Every code this model can display, in one place.

9U53212213217260354357358359364365372373374375376380800808810828A1A1-281A3A7A8b7C1C1-264C4C6C7CECFD1D1-240D1-241D1-286D3D4D4-271E2E2-222E2-223E3E5E5-218E5-332E9E9-219E9-220E9-221E9-224E9-276E9-277E9-285EAEA-227EA-229EA-234EA-261ECEDEEEFEF-349F0F0-237F0-239F0-242F0-256F0-258F0-259F0-262F0-263F0-267F0-272F0-278F0-279F0-280F0-290F0-338F7F7-228F7-328FAFA-306FA-364Fb-365FDFD-231H5P1t1t2t3t4t6

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