15
Installing Differential Return Air Sensor
The CRDIFRASN01A00 differential return air sensor kit must
be field mounted in the system’s return duct work. The kit in-
cludes a wiring harness that connects the EconoMi$er X har-
ness in the return chamber of the unit to the provided
HH57AC081 sensor. Wire per Fig. 33.
In addition to using the HH57AC081 (Honeywell C7400S) sen-
sor (see Fig. 32) for a single enthalpy sensor, it can also be used
as a differential return enthalpy or dry bulb sensor. Figure 31
shows the dual enthalpy boundaries in the W7220 Jade control-
ler. With dual enthalpy, the HIGH LIMIT boundary is ES1 when
there are no stages of mechanical cooling energized and HL
(high limit) when a compressor stage is energized. Table 7
shows the High Limit Curves for each setting.
NOTE: To use the HH57AC081 sensor for differential return air,
the dipswitches on the sensor must be set to ON-OFF-OFF. See
Table 8.
When using the CRDIFRASN01A00 differential return enthal-
py or dry bulb temperature option, see Table 9 for California
Title 24 setting requirements by region.
Fig. 33 — Wiring Differential Return Air Sensor
California’s Title 24 High Temperature Limit
Settings
California’s Title 24 code requires a high temperature limit set-
ting for all dry bulb outside air economizer change over. The
temperatures vary by region within California. See Table 9 for
high limit settings.
*
Only the high limit control devices listed are allowed to be used and
at the set points listed. Others such as Dew Point, Fixed Enthalpy,
Electronic Enthalpy, and Differential Enthalpy Controls, may not be
used in any climate zone for compliance with Section 140.4(e)1
unless approval for use is provided by the Energy Commission
Executive Director.
†
At altitudes substantially different than sea level, the Fixed
Enthalpy limit value shall be set to the enthalpy value at 75°F and
50% relative humidity. As an example, at approximately 6,000 foot
elevation, the fixed enthalpy limit is approximately 30.7 Btu/lb.
Demand Controlled Ventilation (DCV)
Refer to EconoMi$er X wiring diagram (Fig. 25 and 30) and
DCV instructions if demand controlled ventilation (CO
2
sen-
sor) is used. CO
2
sensor will wire into the blue and black con-
nections at the Jade controller as shown in Fig. 25, 30, and 34.
If a field-installed CO
2
sensor is connected to the
EconoMi$er X controller, a demand controlled ventilation
strategy will operate automatically. As the CO
2
level in the
space increases above the set point (on the EconoMi$er X con-
troller), 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 in-
crease in fresh air, the outdoor damper will follow the higher
demand condition from the DCV mode or from the free cool-
ing mode.
Fig. 34 — 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
TABLE 140.4-B AIR ECONOMIZER HIGH LIMIT SHUT OFF
CONTROL REQUIREMENTS
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 temperature
2, 4, 10
OAT exceeds return air
temperature minus 2°F
6, 8, 9
OAT exceeds return air
temperature minus 4°F
7
OAT exceeds return air
temperature minus 6°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