High
9.ii on Chaffoteaux Celtic 24 HE

Your boiler is overheating because water is not moving through the system quickly enough to carry the heat away.

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.

Technical description

Excessive temperature rise across boiler - Low water flow rate (Pump defective/High resistance)

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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