Before doing this we recommend draining the steam boiler. The machine should be unplugged and cool to the touch.
Tools required:
adjustable wrench
wire brush
First, remove the panels.
Before re-installing the panels, plug the machine back in and power on.
On the first start up after cleaning the fill probe, the boiler will likely need to be purged, as it will still be over-full from the last time the machine was used. Don't skip this step!
To do this, start with the machine off and direct the hot water wand into a large pitcher, then fully open the hot water joystick and power the machine on. As the machine reaches full temperature, water will begin to flow from the hot water wand. Wait for ~8-12 fl oz to be dispensed, then flip the hot water joystick to the fully closed position and allow the machine to finish heating as normal.
Check out the instructions for this procedure on a similar machine for more detail!