BoilerFaultCodesWhat the manual says
Manufacturer manualNo heating demand from external controls (clamp 3-4 open)
What causes this fault?
This status occurs when the boiler is powered on and ready to go, but it hasn't received an electrical signal from your wall thermostat or timer to start heating. The most common reason is simply that the room temperature is already higher than the target you've set, or your heating schedule is currently set to an 'off' period.
This is frequently reported during the transition into autumn when homeowners first try to turn their heating back on, only to find the 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 'On' or 'Auto'.Replace the batteries in your wireless thermostat if the screen is blank or showing a low battery symbol.
Avoid the next call-out bill
Monthly cover means no unexpected bills when your boiler breaks down.
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