High
F.89 on Vaillant ecoFIT Pure 435

Your boiler has detected an issue with the internal water pump's connection or electronic signals, causing it 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.

What the manual says

Manufacturer manual

Incorrect pump detected — Unsuitable pump connected, PWM plug not plugged in or has come loose, multiple plug on the PCB not plugged in correctly, interruption in cable harness, electronics defective

From this model's manual
Verified against the Vaillant/Vaillant Ecofit Pure 412 435 Open Vent 0020230535 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

F.22View →F.75View →

All 71 fault codes on the ecoFIT Pure 435

Seeing a different code? Every code this model can display, in one place.

conF.00F.01F.10F.11F.13F.22F.23F.24F.25F.27F.28F.29F.32F.49F.61F.62F.63F.64F.65F.67F.68F.70F.71F.72F.73F.74F.75F.76F.77F.83F.84F.85F.87F.88F.97S.0S.01S.02S.03S.04S.05S.06S.07S.08S.20S.21S.22S.23S.24S.25S.26S.27S.28S.30S.31S.32S.34S.39S.42S.46S.53S.54S.88S.91S.96S.98S.99S.108S.109

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