Emerson Rosemount 3900 Quick Start Manual page 11

May 2023
The electrode tip guard will protect the electrode glass from
breakage.
5. Thread the ferrule fitting tightly into the ball valve assembly.
NOTICE
Do not tighten the hex nut on the ferrule fitting. Tightening
the hex nut would not make it possible to insert the sensor
through the ball valve.
6. Pull back hard on the sensor, as if trying to remove it, to be
certain that the sensor cannot come free of the ball valve
assembly.
If the sensor is properly installed, the built-in retraction stop
will butt against the shoulder of the ferrule fitting.
NOTICE
The sensor must be captured by the valve assembly so that it
cannot be blown free by process pressure if mishandled
during insertion or retraction.
7. After confirming that the sensor assembly is properly secured
by the valve assembly, open the ball valve and position the
sensor into the process at the desired depth and orientation.
8. While holding the sensor in position, tighten the hex nut of the
ferrule fitting to firmly secure the sensor in place.
NOTICE
Over-tightening the hex nut may damage the ferrule.
NOTICE
A stainless steel ferrule is available if the PTFE ferrule does not
adequately grip. When using the metallic ferrule, take care to
avoid over-tightening and damaging the sensor tube. If the
ferrule fitting leaks during insertion or retraction, replace the
O-ring in the ferrule fitting.
When the hex nut is tightened, the PTFE ferrule inside the
ferrule fitting clamps the sensor tube.
Quick Start Guide
Quick Start Guide
11