Special Instructions For Vacuum Ranges
On vacuum ranges, the C-NO circuit is closed at sea level condi-
tions. Therefore, increasing vacuum will cause the C-NC circuit to
close while decreasing vacuum will cause the C-NO circuit
to close. Please make a note of this and wire/adjust the unit
accordingly.
Tools Needed
Screwdriver
NOTE: For set point adjustments and re-calibration, connect
control to a calibrated pressure gauge.
Type J400 & J400K
Remove cover. Switch has screw adjustments inside enclosure.
Increase gauge pressure until switch transfers. To RAISE the
pressure setting turn the screw IN To LOWER the pressure setting
turn the screw OUT. One full turn corresponds to approximately
10% of range on diaphragm and piston models, and approximately
20% of range on bellows models. When making adjustments, do
not exceed the proof* pressure rating on nameplate.
Types J402, J403 & J402K
Remove cover, follow same procedure as paragraph above.
Switches may be set together or apart, up to 100% of range
(maximum separation on models 520-535 is defined in Table 1).
On dual switch, either switch may be set high. On triple switch
models, the third (middle) switch has no over-travel mechanism
and must always be set to the highest pressure when switches are
set apart. Altering the setting of one switch will usually have little
effect on the other(s), however re-calibration may be desired at a
critical pressure setting and after changing switch(es).
Table 1
Special Instructions for Models 520-535
When calibrating the Models 520-535, Switch 2 (the right switch
as viewed from the front of the control) must be set to the higher
pressure value. Use a screwdriver to turn the adjustment screw and
obtain the desired actuation pressure for Switch 2. Switch 1 can
then be set following the procedure outlined for the Type J400 and
J400K. Maximum separation between Switch 1 and 2 is
defined in Table 1.
Types H400, H402, H403, H400K & H402K
Remove cover, switch has knob and pointer adjustment inside
enclosure. Controls are factory calibrated for maximum accuracy at
the dial midpoint. Switches may be set together or apart up to
100% of the range scale. On dual switch models either switch may
be set high. On triple switch models, the third (middle) switch has
no over-travel mechanism and must always be set to the highest
pressure when the switches are set apart. Altering the setting of one
switch will usually have little effect on the other(s), however
re-calibration may be desired at a critical setting or after
changing switch(es).
To re-calibrate, turn pointer to desired set point and add gauge
pressure until switch transfers. If gauge pressure and set point
pressure do not agree, turn zero adjust screw clockwise to raise and
counter clockwise to lower pressure setting (See Figure 2).
Types with Manual Reset (Option 1530)
These optional models incorporate a snap switch that, when actuat-
ed, remains tripped until pressure decreases and the reset button is
manually depressed to the reset position.
Types J400K & J402K with Option M210
(indicator models 147, 157, S147B, S157B only)
To adjust for maximum accuracy at any desired set point, follow
steps 1 - 4 below:
SPAN ADJUSTMENT
1) Remove front window and gasket (four screws)
to gain access to span adjustment.
2) Connect control to calibrated pressure source and set to
required differential pressure.
3) Using a screwdriver, carefully turn span adjustment
(See Figure 3) to obtain required indication.
4) Re-mount front gasket and window.
Tools Needed
Screwdriver
USE ONLY FACTORY AUTHORIZED REPLACEMENT PARTS
AND PROCEDURES. DISCONNECT ALL LIVE CIRCUITS
BEFORE PROCEEDING. COMPONENTS AVAILABLE FOR
REPLACEMENT ARE THE SWITCHES. OTHER COMPONENTS
FACTORY REPLACEABLE ONLY.
Part III - Replacements
Part II - Adjustments
Switch Separation
Model & Range (% of Range Span)
520, 530 (-300 to 0 VAC) 25%
521, 531 (-10 to +10 "wc) 35%
522, 532 (-50 to +50 "wc) 35%
523, 533 (0.5 to 5 "wc) 50%
524, 534 (2.5 to 50 "wc) 50%
525, 535 (10 to 250 "wc) 20%
*Subjecting the switch to proof pressure may cause a shift in set point
REPLACEMENT OF SWITCH(ES)
1) Disconnect leadwires.
2) Remove the two mounting screws. On multi-switch
controls, first remove switch bias springs (See Figure 1.)
3) Insert replacement switch and replace screws
and bias springs.
4) Check switch set point and re-calibrate per
PART II if necessary.
