Low
d.17 on Vaillant ecoTEC plus 612 VU GB 126/3-5

Your boiler is temporarily registering that the pipes carrying hot water for your heating and hot water systems might be set up the wrong way around.

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.

What the manual says

Manufacturer manual

Heating flow/return regulation changeover

From this model's manual
Verified against the Vaillant/Vaillant Ecotec Plus Pro 839592 00 2004 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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Related fault codes

F.20View →F.22View →d.18View →

All 119 fault codes on the ecoTEC plus 612 VU GB 126/3-5

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

d.00d.01d.02d.03d.05d.06d.07d.08d.09d.10d.11d.18d.19d.22d.23d.25d.26d.30d.33d.34d.35d.36d.40d.41d.44d.47d.50d.51d.60d.61d.64d.65d.67d.68d.69d.70d.71d.72d.73d.75d.76d.77d.78d.80d.81d.82d.83d.84d.90d.91d.93d.97F.00F.01F.02F.10F.11F.13F.20F.22F.23F.24F.27F.28F.29F.32F.60F.61F.62F.63F.64F.65F.70F.71F.72F.73F.74F.75F.76P.1P.2P.3P.4P.5P.6S.00S.01S.02S.03S.04S.05S.06S.07S.08S.10S.11S.13S.14S.15S.16S.17S.20S.21S.22S.23S.24S.25S.26S.27S.28S.30S.31S.32S.34S.36S.53S.54S.76

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