Low
S.28 on Vaillant ecoTEC plus Regular

Your boiler has temporarily paused to prevent it from turning on and off too frequently, which helps save energy and protect the internal components.

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

Hotwaterhandlingmode:Temporaryshutdownoftheburner

From this model's manual
Verified against the Vaillant Ecotec Plus Regular installation & service manual, page 32.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This occurs when the boiler has reached its required temperature too quickly and pauses briefly to prevent 'short-cycling.' The most common reason is that the heat generated by the boiler cannot be moved away fast enough, often because radiators are turned off or the system is already up to temperature. By waiting a few minutes before restarting, the boiler prevents unnecessary wear and tear on its internal parts.

This is more common during the autumn and spring when the weather is milder and your home requires less heat to stay warm.

DIY fix possible

Wait for 15-30 minutes for the internal timer to finish its countdown.Check that your radiators are turned up to allow heat to escape the system.Ensure your room thermostat is set high enough to call for heat.

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