Low
d.34 on Vaillant ecoFIT Pure 425

Your boiler is displaying the current fan speed for diagnostic purposes rather than an error, but it may indicate an issue with how the fan is communicating with the system.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

Value for the fan speed

DIY fix possible

Navigate the digital display to your main screenNo action is required as this is a diagnostic statusIf the boiler is not firing, try a single resetMonitor for actual error codes like F.32

Find a Gas Safe engineer
Search the official register →

Related fault codes

F.32View →d.33View →

Related guides you might find useful

Banging / kettling / whistling noise

Each noise points to a different fault.

Read →

Yellow or orange flame — CO safety

Safety-critical — turn off, read this.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →