High
7 flashes on Worcester Bosch Greenstar 25CDi

Your boiler has overheated because the water inside is not moving correctly or has become too hot, causing a safety sensor to shut the system down.

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

Safety temp. limiter in CH flow has tripped. Check system pressure, check safety temp. limiters, check pump operation, check fuse on pcb, bleed appliance.

From this model's manual
Verified against the Worcester Bosch/Worcester Bosch Greenstar 25cdi 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 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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All 21 fault codes on the Greenstar 25CDi

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

2 flashes3 flashes4 flashes5 flashes6 flashes8 flashes9 flashesA7b1C6CH flow NTC sensor defective.Code plug not detected.E2E9F7Fan speed too low.Flame not detected.Internal error.Rapid flashesSlow flashes

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