10
46-620 B73 & Series 75 Liquid Level Switches
11. If differential has been changed in the field by reposition-
ing the lower jam nuts on the float stem, check tightness
and position of the jam nuts. Refer to
Figure 7
on page 5.
NOTE: Differential adjustment affects a change in the amount of level
travel between switch-on and switch-off actuations.
Do not
attempt
adjustment without first consulting factory for assis-
tance in computing level differential change for your control.
12. Check float to be certain it is buoyant in the liquid (float
chamber or vessel must have adequate liquid level). If float
is determined to be filled with liquid, or it is collapsed, it
must be replaced immediately.
Do not attempt to repair a
float.
See
Section 2.5, Tandem Float Models
on page 7.
If all components in the control are in operating condition,
the trouble must be located external to the control. Repeat
inspection of external conditions previously described.
NOTE: If difficulties are encountered which cannot be identified,
consult the factory or your local representative for assistance.
A complete description of the trouble should be provided
along with information concerning your piping and mounting
arrangement, plus a description of your operating sequence.
Sketches or photographs showing the installation are also
beneficial.
When communicating about your control, be certain to
always specify the complete Model and Serial numbers.
4.0
Preventive Maintenance
Periodic inspections are a necessary means to keep your
Magnetrol level control in good working order. This con-
trol is a safety device to protect the valuable equipment it
serves. A systematic program of preventive maintenance
must be implemented when the control is placed into
service. If the following is observed, your control will
provide reliable protection of your capital equipment for
many years.
4.1
What To Do
4.1.1 Keep Control Clean
Be sure the switch housing cover is always in place on the
control. This cover is designed to keep dust and dirt from
interfering with switch mechanism operation. In addition,
it protects against damaging moisture and acts as a safety
feature by keeping bare wires and terminals from being
exposed. Should the housing cover or any seals become
damaged or misplaced, obtain a replacement immediately.
