BoilerFaultCodesYour boiler is receiving a command from your smart thermostat or heating controller that it cannot currently process, often due to a communication glitch or a sensor reading incompatibility.
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: Set flow temperature: Setting value of the flow temperature demanded by the heating controller.
What causes this fault?
This fault happens when the boiler and your smart thermostat stop speaking the same language, usually because the controller is asking for a water temperature that the boiler cannot safely provide. It is often caused by a temporary communication glitch between the wireless receiver and the main control board, or a sensor that is sending inconsistent data. Essentially, the boiler has received an instruction it doesn't understand, so it pauses that specific command to protect itself.
DIY fix possible
Check that your room thermostat or smart hub is powered on and has batteriesTurn your boiler off and on again using the power button to reset the communication linkEnsure your smart heating schedule is not requesting an impossibly high temperature
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A boiler cover plan would cover faults like 1-A6 — no call-out fees, no surprises.
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