What does the Vaillant D.51 fault code mean?

Your boiler is flagging a minor technical adjustment error regarding its internal fan speed settings.

How much does it cost to fix Vaillant error code D.51?

Typical repair cost for the Vaillant D.51 fault is £80-160 including labour.

Vaillant D.51 Fault Code: What It Means & How to Fix It

What the manual says

Manufacturer manual

Offset for maximum speed

From this model's manual

Verified against the Vaillant/Vaillant Ecotec Plus Pro 839592 05 2006 installation & service manual.

What causes this fault?

This fault occurs when the boiler's control board detects that the internal fan is operating at a speed that doesn't match the expected safety settings. It is usually caused by an electronic communication error between the main circuit board and the fan, or a slight decalibration in how the gas valve is being controlled. While the boiler may still operate, it signifies that the internal components are not perfectly synced.

Engineer required

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

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Related fault codes

D.50View →F.22View →F.28View →

All 135 fault codes on the ecoTEC plus 612 R1 VU GB 126/3-5

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

35 96 con Connection D,11 D.0 D.1 D.2 D.3 D.4 D.5 D.7 D.8 D.9 D.10 D.12 D.13 D.17 D.18 D.20 D.22 D.23 D.25 D.27 D.28 D.30 D.33 D.34 D.35 D.40 D.41 D.44 D.47 D.50 D.60 D.61 D.64 D.65 D.67 D.68 D.69 D.70 D.71 D.72 D.75 D.76 D.77 D.78 D.80 D.81 D.82 D.83 D.84 D.90 D.91 D.93 D.96 D.97 F.0 F.1 F.10 F.11 F.13 F.20 F.22 F.23 F.24 F.25 F.27 F.28 F.29 F.32 F.49 F.61 F.62 F.63 F.64 F.65 F.67 F.70 F.71 F.72 F.73 F.74 F.75 F.76 F.77 F.78 F70 P.0 P.1 P.2 P.3 P.4 P.5 P.6 S. 2 S. 5 S.0 S.1 S.3 S.4 S.6 S.7 S.8 S.10 S.11 S.13 S.14 S.15 S.16 S.17 S.20 S.21 S.22 S.23 S.24 S.25 S.26 S.27 S.28 S.30 S.31 S.32 S.34 S.36 S.41 S.42 S.52 S.53 S.54 S.96 S.97 S.98

Your boiler is flagging a minor technical adjustment error regarding its internal fan speed settings.

What the manual says

What causes this fault?

Engineer required

Avoid the next call-out bill

Related fault codes

All 135 fault codes on the ecoTEC plus 612 R1 VU GB 126/3-5

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