Low
d.2 on Vaillant ecoMAX 635

Your boiler is currently in a forced waiting period to prevent it from cycling on and off too frequently, which is usually a normal part of its operation.

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 system max. off-period

From this model's manual
Verified against the Vaillant/Vaillant Ecomax 613 installation & service manual, page 47.
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

d.1View →

All 88 fault codes on the ecoMAX 635

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

d.0d.1d.5d.7d.8d.10d.11d.13d.14d.16d.22d.23d.24d.25d.34d.35d.40d.41d.44d.46d.47d.60d.61d.67d.68d.69d.71d.72d.73d.80d.81d.82d.83F.0F.1F.10F.11F.13F.20F.22F.23F.24F.25F.27F.28F.29F.32F.60F.61F.62F.63F.64F.65F.67P.1P.2P.5S.0S.1S.2S.3S.4S.5S.6S.7S.8S.10S.11S.13S.14S.16S.17S.20S.21S.23S.24S.26S.27S.28S.30S.32S.34S.36S.37S.39S.53S.54

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