High
E12 on Warmflow Agentis External

Your boiler has lost communication with the temperature sensor that monitors your hot water tank, meaning it cannot safely heat your water.

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

Tank Control NTC Error — tank control NTC temperature sensor short circuit or disconnected; consult Service Engineer

From this model's manual
Verified against the Warmflow Agentis Internal 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

E11View →E13View →

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