System Sensor EPS40EXP and EPS120EXP - Manual (Page 3)

Adjustments To Factory Settings
Table 2.
Dual-switch Model — EPS40EXP and EPS120EXP
1. Install pressure switch as stated in “INSTALLATION”
portion of instruction manual. Attach pressure test
source to system.
2. Remove adjustment wheel cover and back off locking
screw (see Figure 1) to allow main adjustment wheel to
rotate freely.
3. Option 1: To adjust the nominal setting of the pressure
window (low switch setting to high switch setting)
without affecting the size of the window, adjust the
main adjustment wheel, Figure 1, to the desired setting
using the pressure source to verify each switch setting.
Each tine on the wheel represents an approximate win-
dow shift of 1.8 PSI for the EPS40EXP and 6.6 PSI for the
EPS 120EXP. For each 1/2 rotation of the adjustment
wheel, the window changes by approximately 11 PSI for
the EPS 40EXP and 40 PSI for the EPS 120EXP.
Option 2: To adjust the pressure window size and the
nominal setting of the pressure window, adjust the main
adjustment wheel, Figure 1, until the high switch (SW1)
trips at the desired pressure using the pressure test
source. Decrease the pressure until the low switch
(SW2) trips. Note pressure and determine how much
change is desired on the low switch. Adjust the 1/4″ hex
screw, Figure 1, to either increase (counterclockwise) or
decrease (clockwise) the window size. (The low switch
will be affected.) The approximate sensitivity of the hex
screw adjustment: 1/2 turn = 5 PSI. An approximate
maximum window size of 30 PSI is obtainable. Retest
the high switch after adjusting the low switch.
4. Retest the set points several times to ensure the accura-
cy of the settings.
5. Re-seat locking screw.
6. Re-install adjustment wheel cover.
NOTE: The sensor assembly is not field replaceable. Do
not attempt to disassemble these parts. If you have
any questions, consult System Sensor. System
Sensor recommends careful consideration of the
following factors when specifying and installing
Alarm and Supervisory Pressure Switches. Always
refer to the Installation and Maintenance
Instruction for specific recommendations on indi-
vidual devices before installing the unit.
• Electrical ratings stated in literature and on name-
plates should not be exceeded.
• Overload on switch can cause failure on the first
cycle. Always wire devices according to national and
local electrical codes.
• Install units away from shock and vibration. Proper
electrical fittings should be used to prevent moisture
from entering the enclosure via the conduit.
• Test all devices for proper operation after initial instal-
lation. Perform preventive maintenance and periodic
testing as required by the applicable NFPA standards
but not less than bi-monthly.
• Install a back-up control for all critical applications
where control failure could endanger life or property.
A backup control to serve as a high or low limit con-
trol is especially recommended for applications where
a runaway condition could result.
• Do not mount unit where ambient temperatures will
exceed published limits.
• Avoid impact or mechanical loading.
FACTORY SETTINGS ( PSI)
MODEL Fall Sw2 Nominal Rise Sw1
(Low Switch) (Hi Switch)
EPS40EXP 30 ± 1.5 40 50 ± 2.5
EPS120EXP 101.5 - 112.5 115 117.5 - 128.5
D770-26-00 3 I56-1428-001R