Your boiler is working perfectly and is simply waiting for a signal from your thermostat or programmer to turn the heating on.
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: no heating required
What causes this fault?
This code appears when the boiler has successfully completed its previous task and is now in 'standby' mode. It is physically waiting for the external controls, such as your room thermostat or timer, to click on and request heat. Until that signal is sent, the boiler remains idle to save energy and prevent overheating.
This code is frequently seen during the summer months or warmer transitional periods when the house is already at the desired temperature and the heating isn't needed.
DIY fix possible
Check that your room thermostat is turned up higher than the current room temperature.Ensure your heating programmer or timer is set to an 'On' period.Check if the batteries in your wireless thermostat need replacing.
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