BoilerFaultCodesYour boiler has entered a specific maintenance mode or sensor test, meaning it is not operating in its normal heating cycle.
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: Service Function: Switching difference
What causes this fault?
This code appears when the boiler has been manually or accidentally switched into a specific service mode that adjustments the burner's firing behavior. It is usually triggered by someone interacting with the internal settings or the control dials in a specific sequence, rather than a mechanical component failing. While in this mode, the boiler pauses its normal operation to allow an engineer to test the temperature gaps between the flow and return pipes.
DIY fix possible
Turn the temperature control dials fully counter-clockwise and then back to your desired settingPress and hold the 'Reset' button for five secondsSwitch the main power supply to the boiler off and back on again after 30 seconds
Find a Gas Safe engineer
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A boiler cover plan would cover faults like 2.6 — no call-out fees, no surprises.
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