High
E14 on Halstead Netaheat 10/16E

Your boiler is struggling because it cannot balance the temperature between the water leaving and returning to the unit, suggesting a potential flow restriction or sensor disagreement.

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

Differential between flow and return thermistors too high

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

E11View →

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