Low Information
S.28 on Vaillant ecoMAX 622

Your boiler is taking a short, planned break to prevent it from turning on and off too frequently, which helps protect the internal components and improve efficiency.

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

Anti cycling mode (warm start)

What causes this fault?

This status occurs when the boiler has reached its target temperature and shuts the burner off to prevent overheating. It enters a programmed pause to stop the system from 'short cycling,' which is when the unit rapidly switches on and off. This delay allows the water in your radiators to cool slightly before the boiler fires up again, reducing unnecessary wear and tear.

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

DIY fix possible

Wait approximately 10 to 15 minutes for the timer to count down naturallyCheck that your room thermostat is turned up high enough to call for heatEnsure your radiator valves are open to allow heat to dissipate

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