![Magnetrol C29 Installation And Operating Manual Download Page 8](http://html2.mh-extra.com/html/magnetrol/c29/c29_installation-and-operating-manual_3593722008.webp)
8
46-605 Flanged External Cage Float Actuated Liquid Level Switches
The differential, or the amount of level travel between
switch-on and switch-off, may be adjusted by reposition-
ing the lower jam nuts on the float stem. This adjustment
is different for high level and low level controls. Refer to
the appropriate section below for adjustment instructions.
NOTE: Maximum differential adjustment is 1 inch.
Caution:
Differential adjustments should NOT be made in the field
on tandem float models. Switch actuation levels have
been set at the factory to meet customer specifications.
Variations in actual conditions from design conditions,
usually require special control modifications. Consult the
factory or your local representative for assistance.
2.4.1 Low level controls
On low level controls the switch trips on the lower actua-
tion point and resets on the higher actuation point.
Widening the differential will allow the switch to trip on
the original actuation point and reset at a later or higher
point.
The differential on low level controls may be adjusted by
repositioning the lower jam nuts on the float stem. The
standard factory setting is for a minimum amount of play
(gap) between the top jam nuts and the attraction sleeve.
Refer to
Figure 7
.
1. Determine what change in differential is necessary.
NOTE: To widen the differential by one inch, the lower jam nuts must
be set proportionately lower on the stem (i.e., in this example
by 1 inch).
2. Make sure power source is turned off.
3. Unscrew and remove switch housing cover.
4. Disconnect power supply wires from switch mechanism.
Pull wires out of conduit connection opening in housing
base. Refer to
Figure 8
.
5a. Perform system shut-down procedures as required to relieve
pressure from float chamber of control. Allow unit to cool.
5b. Close shut-off valves (if so equipped) to isolate control
from tank. Drain off liquid in float chamber.
5c. On installations without shut-off valves, relieve pressure
from the tank. Drain liquid in tank to a level below the
connections of the float chamber.
NOTE: Level control, connections and pipe lines need not be
removed from the tank.
6. Loosen enclosing tube nut with a
15
⁄
16
" wrench. Unscrew
enclosing tube counterclockwise (switch and housing base
will rotate also), until it is free. Refer to
Figure 8
.
Figure 7
Differential adjustment
For access to bottom
jam nuts, remove top
jam nuts, washer, and
attracting sleeve.
Slight play (gap)
must be allowed
(.03" [.8 mm] typical)
Position of bottom
jam nuts (normal
factory setting)
Float
Sleeve stop
strap
Replace in
same position
Drop bottom jam nuts to
increase gap setting
(see instructions below)
0.50"
(13 mm)
Maximum gap setting
(Applies to models having
a single switch mechanism
with a single magnet
actuator only)
Float
Sleeve stop
strap
D
Figure 6
Normal Factory Setting
(minimum differential)