High
A1 on Worcester Bosch Greenstar Cdi 40 Cdi

Your boiler has stopped because there isn't enough water circulating inside the system to keep it running safely.

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

Pump has run dry. Check system pressure, add water and bleed system as necessary.

From this model's manual
Verified against the Worcester Bosch/Worcester Bosch Cdi Rsf installation & service manual, page 56.
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 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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Related fault codes

CEView →E9View →

All 11 fault codes on the Greenstar Cdi 40 Cdi

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

A2A7b1C1C6E2E9EAF7FA

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