High
F.0 on Vaillant Ecomax Condensing 600/800 series

Your boiler's temperature sensor is failing to provide a reading, which has caused the system to shut down for safety.

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

Flow–NTC: – NTC broken – NTC cable broken – Defective connection at NTC – Defective connection at electronics | Flow–NTC cable defective/broken NTC faulty

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

F.1View →

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