High
F.064 on Vaillant ecoTEC plus

Your boiler has detected an internal error where it can no longer accurately read the temperature or pressure data it needs to operate 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.

What the manual says

Manufacturer manual

Sensor defective. The sensor signal could not be converted correctly.

From this model's manual
Verified against the Vaillant Ecotec Plus installation & service manual, page 86.
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

F.061View →F.062View →F.065View →

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