D.67 Low

Vaillant D.67 Fault Code

Also written as D67 — same fault.

The Vaillant D.67 fault code means: your boiler is simply taking a short, programmed break between heating cycles to protect its internal parts and operate more efficiently.. It appears on 25 Vaillant models in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Remaining burner anti-cycling time

What causes the Vaillant D.67 fault?

This occurs because the boiler has reached its target temperature and has temporarily shut down to prevent the system from turning on and off too frequently. It is a built-in safety feature designed to reduce wear and tear on the internal components and improve fuel efficiency. The boiler will automatically resume heating once a pre-set cooling period has passed.

This is more common during the 'shoulder' months of spring and autumn when the weather is mild and the boiler needs to produce less heat to keep your home warm.

DIY fix possible

Wait for 5 to 15 minutes for the countdown to finishEnsure your room thermostat is turned up high enough to call for heatCheck that your radiator valves are open to allow heat to dissipate

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Vaillant models that show the D.67 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Vaillant D.67 fault code information on this page is sourced and cross-checked against the official Vaillant service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026