Medium
S.54 on Vaillant ecoMAX

Your boiler has temporarily stopped itself because it has detected an issue with the water pressure or flow, and it is now waiting for a short period before it attempts to start again.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Appliance is within the waiting period of the operation block function due to water shortage (temperature gradient)

From this model's manual
Verified against the Vaillant Ecomax installation & service manual, page 45.
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 the pressure gauge on the front of the boiler; if it is below 1 bar, locate the filling loop.Open the filling loop valves to increase the system pressure to between 1 and 1.5 bar.Close the valves tightly and check the boiler display to see if the error clears.

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