10
46-622 Series 3 Liquid Level Switches ASME B31.3 Construction
To widen the differential by raising the trip point, follow
steps 1 through 16 in
Low Level Controls
,
Section 3.1,
pages 8–9).
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 a necessary means to keep your
level control in good working order. This control is a safety
device to protect the valuable equipment it serves. A sys-
tematic program of “preventive maintenance” must be
implemented 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 equipment for many years.
4.1
Recommended Practice
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.
4.1.2 Inspect Switch Mechanisms, Terminals, and
Connections Monthly
1. 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. See switch
mechanism bulletin supplied with control should switch
adjustment or replacement be necessary.
2. DO NOT operate your control with defective or mal-
adjusted switch mechanisms. Refer to the
Switch
Instruction Reference Bulletins
chart on page 7 to find
appropriate bulletins for service instructions.
3. Level controls may sometimes be exposed to excessive
heat or moisture. Under such conditions, insulation on
electrical wiring may become brittle, eventually breaking
or peeling away. The resulting “bare” wires can cause
short circuits.
NOTE: Check wiring carefully and replace at the first sign of brittle
insulation.