Installation manual

035-16682-000-E-0303
Unitary Products Group 19
EXHAUST STATIC PRESSURE
The exhaust air side static pressure switch is located on a
bracket mounted in the return air compartment. Plastic tubing
(1/4") must be run from the high pressure tap of the static
pressure switch to a static pressure tap located in the condi-
tioned space or return air duct at a point where constant pres-
sure is desired. Tubing must also be run between the low
pressure tap of the switch to atmospheric pressure.
EXHAUST POSITIVE / NEGATIVE STATIC PRES-
SURE
The null pressure switch is factory wired to provide a positive
pressure setpoint. In this configuration, connect the low side
pressure switch port to the atmosphere and the high side
switch port to the building pressure tap.
To set the control to a negative building static pressure the
following changes are necessary:
1. Connect the low side port to the building pressure and
high side to atmosphere.
2. The wires connected to the switch output must be
reversed. Purple wire #323 (factory wired to HI terminal)
must be moved to the LO terminal of SSP2. White wire
#350 (factory wired to LO terminal) must be moved to the
HI terminal of SSP2.
The static pressure switch only has positive setpoints. Making
the above change enables negative control because the
switch diaphragm detects a positive pressure when the ports
are reversed.
FIGURE 13 - ENTHALPY CONTROLS
Do not run plastic tubes in the supply or return air
ducts as air movement could cause erroneous
sensing. If tubes penetrate bottom of unit be sure
openings are sealed against air and water leak-
age.
FIGURE 14 - DRY BULB SETPOINT ADJUSTMENT
40
45
50 55 60 65 70 75
80 85 90
95 100
9
10
11
12
13
14
15
16
17
18
19
LED O N
LED O N
LED O FF
LED O N
LED O FF
C
LED O N
LED O FF
LED O FF
D
DEGREES FAHRENHEIT
mA
LED O N = FREE CO OLING AVAILABLE (ECO N)
LED OFF = USE M ECHANICAL COOLING (NO ECON)
N O TE: A, B, C , D , A R E 7210D S W ITC H IN G S ETP O IN TS .
A
B