If the float is a simple switch mechanism and opens or closes
at trip level you could wire in a LED with a series R and diode,
across the float leads to controller. Such that if contacts close
LED goes out or if contact open LED turns on, and use that light
or its absence to trigger your status display via a photocell. Like a
night5light in a bathroom. That way you are isolated from the
controller and its HV, and can do pretty much anything with the
float status led output.
If you need to remote the display of status use consumer grade optical fiber link like
TOSLINK.
Or use a simple relay across the float contacts to turn on off an indicator.
I think you have to confirm with the controller guys if the float is tripped
it has 0V across it and when not tripped 110 VAC or the opposite.
Regards, Dana.