With the machine powered on and heating you can press and hold the boiler button for 3-5 seconds to turn the steam boiler off or a single press to turn it on. You will know that the steam boiler is heating when the word "BOILER" is lit in bright red or flashing bright red to indicate that it is heating. When the word "BOILER" is not lit then the boiler is off and not heating.
Note: If you see a dim red bleeding from other touchpad lights that does not indicate heating function. When it is lit it is a clear bright red.