14
Installing Differential Return Air Sensor
The CRDIFRASN01A00 differential return sensor kit
must be field mounted in the system’s return duct work. The
kit includes a wiring harness, that connects the EconoMi$er
X harness in the return chamber of the unit, to the provided
HH57AC081 sensor. Wire per Fig. 31.
In addition to using the HH57AC081 (Honeywell
C7400S) sensor (Fig. 30) for a single enthalpy sensor, it can
also be used as a differential return enthalpy or dry bulb sen-
sor. Figure 29 shows the dual enthalpy boundaries in the
W7220 Jade controller. With dual enthalpy the high limit
boundary is ES1 when there are no stages of mechanical
cooling energized and HL (high limit) when a compressor
stage is energized. Table 7 shows the High Limit Curves for
each setting. Important: to use the HH57AC081 sensor for
differential return air, the dipswitches on the sensor must be
set to ON-OFF-OFF. See Table 8.
When using the CRDIFRASN01A00 differential return
enthalpy or dry bulb temperature option, see Table 9 for Cali-
fornia Title 24 setting requirements by region.
Fig. 31 — Wiring Differential Return Air Sensor
California’s Title 24 High Temperature Limit
Settings
California’s Title 24 code requires a high temperature limit
setting for all dry bulb outside air economizer changeover.
The temperatures vary by the region within California. See
Table 9 for high limit settings.
*
Only the high limit control devices listed are allowed to be used and
at the setpoints listed. Others such as Dew Point, Fixed Enthalpy,
Electronic Enthalpy, and Differential Enthalpy Controls may not be
used in any climate zone for compliance with Section 140.4(e)1
unless approval for use is provided by the Energy Commission
Executive Director.
†
At altitudes substantially different than sea level, the Fixed Enthalpy
limit value shall be set to the enthalpy value at 75°F and 50% rela-
tive humidity. As an example, at approximately 6,000 foot elevation,
the fixed enthalpy limit is approximately 30.7 Btu/lb.
Demand Controlled Ventilation (DCV)
Refer to EconoMi$er X wiring diagrams Fig. 23 and 28 and
DCV instructions if demand control ventilation (CO
2
sensor) is
used. CO
2
sensor will wire into the blue and black connections
at the Jade controller as shown in Fig. 23, 28, and 32. If a field-
installed CO
2
sensor is connected to the EconoMi$er X con-
troller, a demand-controlled ventilation strategy will operate
automatically. As the CO
2
level in the space increases above
the setpoint (on the EconoMi$er X controller), the minimum
position of the dampers will be increased proportionally, until
the Maximum Ventilation setting is reached. As the space CO
2
level decreases because of the increase in fresh air, the outdoor
damper will follow the higher demand condition from the DCV
mode or from the free cooling mode.
Fig. 32 — CO
2
Wiring Connections to Jade
Controller
12-PIN FEMALE
PLUG FROM ECONOMIZER
BLU
BLK
GRA
GRA
GRA
GRA
GRA
GRA
GRA
PNK
VIO
6
7
2
3
10
11
5
1
12
9
4
8
RED
ORG
PL6
PLUG
12-PIN MALE
PLUG IN UNIT
BRN
YEL
*HH57AC081
DIFFERENTIAL RETURN
SENSOR. FIELD MOUNTED
IN RETURN DUCT
WIRING
HARNESS*
*PROVIDED IN
CRDIFRASN01A00 Kit
Table 9 — California Title 24 Regional High Limit Dry
Bulb Temperature Settings
DEVICE TYPE*
CLIMATE
ZONES
REQUIRED HIGH LIMIT
(ECONOMIZER OFF
WHEN):
DESCRIPTION
FIXED DRY BULB
1, 3, 5, 11-16
OAT exceeds 75°F
2, 4, 10
OAT exceeds 73°F
6, 8, 9
OAT exceeds 71°F
7
OAT exceeds 69°F
DIFFERENTIAL DRY
BULB
1, 3, 5, 11-16
OAT exceeds RA Temp.
2, 4, 10
OAT exceeds -2°F
6, 8, 9
OAT exceeds -4°F
7
OAT exceeds -4°F
FIXED ENTHALPY† +
FIXED DRY BULB
ALL
OAT exceeds 28 Btu/lb of dry
air or OAT exceeds 75°F
BLACK WIRE
IAQ 2-10 VDC
BLUE WIRE
IAQ COM
