High
25E on Ravenheat 120

Your boiler has detected that the water inside the main heating unit has likely frozen due to extremely cold weather, preventing it from operating 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.

Technical description

Main heat exchanger frozen

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

05EView →06EView →

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