INSTALLATION cont.
WIRING cont.
Terminal connections shown in Figure 4 are for a standard
SPDT switch. Actuating the switch closes one circuit and
simultaneously opens the second circuit. In this diagram,
circuit between contacts 4 and 5 is made and circuit
between contact 5 and 6 is broken at low liquid level. At
high level, circuit between contacts 4 and 5 is broken and
circuit between contact 5 and 6 is made.
Close on
Falling Level
Load
Common
Close on
Rising Level
GREEN
Line
Ground
Assembly B
4 RED
5 YELLOW
6 BLUE
Internal
Circuit
Load
Figure 4
DIFFERENTIAL ADJUSTMENT
The amount of level travel between “switch on” and “switch
off” can be reduced from the maximum factory setting by
raising the lower set of jam nuts. Minimum free play (differ-
ential) of magnetic sleeve is
1
⁄
32
".
CAUTION:
Before attempting any work on the control,
be certain to pull disconnect switch or otherwise assure
that electrical circuit(s) through control is deactivated.
Close operating medium supply valve on controls equip-
ment with pneumatic switch mechanisms.
4. With switch housing removed, jam nuts and magnetic
sleeve are now accessible, as shown in Figure 6.
Raising the lower jam nuts will reduce the differential. As
the first step in any adjustment procedure, the position
of the upper and lower jam nuts should be established.
NEVER CHANGE SETTING OF UPPER JAM NUTS AS
THEY SUPPORT FLOAT ASSEMBLY SO THAT IT CAN-
NOT TOUCH BOTTOM OF CHAMBER.
5. Loosen and remove upper jam nuts, guide washer, and
magnetic sleeve. Lower jam nuts may now be adjusted
to reduce the differential.
NOTE: Be certain to tighten jam nuts securely after adjustment.
6. Replace magnetic sleeve on stem and position upper jam
nuts to their original setting. Lock upper jam nuts to guide
washer.
7. Reassemble control in reverse of steps 1 through 3, previ-
ously described.
8. Test switch actuation by varying liquid level in tank or vessel.
1. Disconnect wiring from supply side of switch mecha-
nism and electrical conduit or operating medium line
connections to switch housing.
2. Perform system shut-down as required to relieve pres-
sure from tank or vessel and drain off liquid “head”
above control mounting position. Allow unit to cool.
3. Remove switch housing assembly by loosening enclos-
ing tube nut located immediately below housing base.
Refer to Figure 8 on page 7.
INSTALLATION SHOWING LEVEL CONTROL (OR ALARM) ON A RECEIVER
From Condenser
Receiver
Chamber mark indicates
actuating level
Desired
Actuating Level
Insulation
DO NOT
Insulate
Switch Housing
Jam nuts.
Slight play (gap)
must be allowed
(.03" [.8 mm] typical)
Differential gap
Magnetic sleeve
To Evaporator
Side View
End View
Figure 6
Mount control so mark on chamber corresponds to level desired
in vessel. When control is used on a low temperature liquid,
chamber and connection lines should be insulated as shown to
prevent “boiling” in the float chamber and false level indications
Figure 5
3
MAGNETROL [ MAGNETROL INTERNATIONAL, INC. ]
