High
F.02 on Vaillant ecoTEC plus aquaPLUS

Your boiler's hot water sensor has stopped communicating with the main control board, meaning the system can no longer tell how hot your water is.

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

DHW-NTC: NTC broken; NTC cable broken; Defective connection at NTC; Defective connection at electronics | DHW- NTC cable defective/ broken NTC faulty

From this model's manual
Verified against the Vaillant Ecotec Plus Aquaplus installation & service manual, page 41.
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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