High
A1 on Worcester Bosch Junior 28i

Your boiler has detected that it is running without enough water inside, which is often caused by a leak or a pump that has jammed or failed.

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

Water is leaking or the pump needs replacing or freeing due to the pump running dry.

From this model's manual
Verified against the Worcester Bosch Junior 28i 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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Related fault codes

EAView →CE 207View →F0View →

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