Low
d.17 on Vaillant ecoTEC Plus 836

Your boiler is currently configured to monitor the temperature of water returning from your heating system rather than the water leaving it, which is a specific setting typically used for underfloor heating systems.

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

Heating control: off=Flow temperature, on=Return temperature (adjustment for underfloor heating)

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.18View →

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