Unknown
F.78 on Vaillant ecoFIT sustain 830

Vaillant ecoFIT sustain 830 fault code F.78

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

What the manual says

Manufacturer manual

Interruption to DHW outlet sensor at external control UK link box is connected, but domestic hot water NTC not bridged

From this model's manual
Verified against the Vaillant/Vaillant Vaillantpro Ecofit Sustain Combi Installation And Maintenance In 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 fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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All 43 fault codes on the ecoFIT sustain 830

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

ConnectionF.00F.01F.10F.11F.12 and F.91F.13F.20F.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.86F.87F.88F.89F.97S.04S.14

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