AEC SM720 Operation Instructions Manual page 12

Alex Electronics Co.
Installation in pipe
When installing the SM720 in narrow pipes make sure that the
pipe is connected to the earth and that there is a venting hole near
its top to vent the air inside the pipe and allow the product to rise
inside it.
Review the following figure for more illustration
1
Fig.5: Installing in a shaft
. 1 Venting Hole
i
NOTE
Don't cover the fitting thread with any insulating material, like
Teflon, in order not to affect the sensor operation. If necessary,
connect the earth terminal in the electronic card to the vessel body
In case of non-conductive vessels connect the sensor to an
outside earth plate
9
SM720 Capacitive Level Transmitter