10
46-624 Series 3 Liquid Level Switches ASME B31.1 Construction
To widen the differential by raising the trip point, follow
steps 1 through 16 in
Low Level Controls, Section 3.1
on
pages 8 and 9.
Caution:
After increasing gap setting, be certain to check for
proper operation of switch mechanism by raising and low-
ering float assembly. Magnet must "snap" cleanly with
additional float movement available after magnet snaps.
4.0
Preventive Maintenance
Periodic inspections are necessary to keep your level con-
trol in good working order. This control is a safety device
to protect the valuable equipment it serves. A systematic
program of “preventive maintenance” must be implement-
ed when the control is placed into service. If the following
sections on “what to do” and “what to avoid” are observed,
your control will provide reliable protection of your equip-
ment for many years.
4.1
What To Do — Every 6 Months (minimum)
4.1.1 Switch Corrosion Inspection
For every 6 months in service, conduct the following
maintenance and inspection checks.
NOTE: Conduct this inspection every 3 months for applications
where the switches are exposed to corrosive environments.
Some environments may cause accelerated corrosion on
the switch mechanism. To identify switch corrosion
prior to failure:
1. Disconnect power to the switch.
2. Remove switch housing cover to inspect switch mecha-
nisms for visible signs of corrosion on terminals and wires.
NOTE: When removing switch housing cover, secure housing base to
prevent rotation of the base and enclosing tube. If cover
proves difficult to remove, loosen housing base set screws
before using a crossbar to free the cover. Loosening the set
screws will prevent accidental rotation of the enclosing tube
and possible leakage of process media.
3. Dry contact switches should be inspected for excessive
wear on actuating lever or misalignment of adjustment
screw at point of contact between screw and lever. Such
wear can cause false switch actuating levels. Adjust switch
mechanism to compensate (if possible) or replace switch.
