BoilerFaultCodesWhat the manual says
Manufacturer manualHot water flow temperature reading
From this model's manual
Verified against the Vaillant Ecotec installation & service manual.
What causes this fault?
This is a status code rather than a mechanical failure, occurring when the boiler sensor detects a demand for hot water. It simply means the internal computer is measuring and displaying the temperature of the water currently being heated for your taps or shower. You will see this code every time you turn on a hot tap as part of the boiler's standard operating sequence.
DIY fix possible
No action is required as this is a status code, not a fault.If the boiler is stuck on this code and not providing heat, try resetting the boiler.Ensure your hot water taps are fully closed.
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