Low
S.0 on Vaillant ecoMAX 824E

Your boiler is working correctly but is currently idle because it hasn't been told to turn on by your thermostat or timer.

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

No heat demand (heating operation)

From this model's manual
Verified against the Vaillant Ecomax 613 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.

What causes this fault?

This code appears when the boiler system is functioning correctly but is waiting for a command from your external controls. It physically occurs because the electrical circuit between your thermostat or programmer and the boiler is open, signaling that your home is already at the desired temperature. The most common reasons for this staying on screen when you want heat are depleted thermostat batteries or a programmer set to the 'off' position.

This status is frequently seen during the transition into autumn when homeowners first try to turn their heating back on, only to find their thermostat batteries have died over the summer.

DIY fix possible

Check that your room thermostat is turned up higher than the current room temperature.Ensure your central heating programmer or timer is set to an 'ON' period.Check if the batteries in your wireless thermostat need replacing.

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