What does the Vaillant d.75 fault code mean?

Your boiler has spent too long trying to heat your hot water tank, so it has temporarily paused this process to ensure your radiators stay warm.

How much does it cost to fix Vaillant error code d.75?

Typical repair cost for the Vaillant d.75 fault is £100-200 including labour.

Manufacturer manual

Maximum hot water priority operation time (Vantage only) 20, 21, 22 … 90 min (factory-adjusted to: 30 min)

Shared across the range

This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Boiler cover options

A cover plan would handle faults like d.75: no call-out fees, no surprise bills.

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

Almost always a stuck diverter valve on combis.

Work through these before the call-out.

Sludge build-up — needs flushing, not bleeding.