Low
d.41 on Vaillant Ecomax Condensing 600/800 series

Your boiler is simply displaying the current temperature of the water returning to the system, which is a status readout rather than a fault.

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

Actual return temperature

From this model's manual
Verified against the Vaillant Ecomax Condensing 600 800 Series 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.

DIY fix possible

Check your boiler display manual to see if you have accidentally entered the diagnostic menuPress the 'i' button or the 'Reset' button (if applicable) to return the display to the standard temperature readoutEnsure your system pressure is at the correct level of 1-1.5 bar

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