Carrier 48HC D17 Series Service And Maintenance Instructions page 57

CONTROL
EXH
N1
Set
N
2V 10V
EXH
P1
P
Min
Pos
T1
Open
T
DCV
Max
2V 10V
AQ1
DCV
AQ
DCV
Set
SO+
2V 10V
SO
Free
SR+
Cool
B C
SR
D
A
Fig. 74 - - EconoMi$er IV Control
Differential Enthalpy Control
For differential enthalpy control, the EconoMi$er IV
controller uses two enthalpy sensors (HH57AC078 and
CRENTDIF004A00), one in the outside air and one in the
return air duct. The EconoMi$er IV controller compares
CONTROL POINT
CURVE
APPROX. deg. F (deg. C)
AT 50% RH
A 73 (23)
B 70 (21)
C
67 (19)
D 63 (17)
65
(18)
60
(16)
A
55
(13)
B
50
C
(10)
45 D
(7)
40
(4)
35
(2)
35 40 45 50 55 60 65
(2) (4) (7) (10) (13) (16) (18)
APPROXIMATE DRY BULB TEMPERATURE--degrees F (degrees C)
Fig. 73 - - Enthalpy Changeover Setpoints
TR TR1
24 24 Vac
Vac
COM
HOT
_
+
1 2
5
4
3
EF EF1
C06038
85 90 95 100 105 110
(29) (32) (35) (38) (41) (43)
80
(27)
75
(24)
70
(21)
A
B
C
D
70 75 80 85 90 95 100 105 110
(21) (24) (27) (29) (32) (35) (38) (41) (43)
the outdoor air enthalpy to the return air enthalpy to
determine EconoMi$er IV use. The controller selects the
lower enthalpy air (return or outdoor) for cooling. For
example, when the outdoor air has a lower enthalpy than
the return air, the EconoMi$er IV opens to bring in
outdoor air for free cooling.
Replace the standard outside air dry bulb temperature
sensor with the accessory enthalpy sensor in the same
mounting location. See Fig. 64. Mount the return air
enthalpy sensor in the return air duct. See Fig. 72. Wiring
is provided in the EconoMi$er IV wiring harness. See Fig.
65. The outdoor enthalpy changeover setpoint is set with
the outdoor enthalpy setpoint potentiometer on the
EconoMi$er IV controller. When using this mode of
changeover control,
potentiometer fully clockwise to the D setting.
Indoor Air Quality (IAQ) Sensor Input
The IAQ input can be used for demand control ventilation
control based on the level of CO
or return air duct.
Mount the accessory
manufacturer specifications. The IAQ sensor should be
wired to the AQ and AQ1 terminals of the controller.
Adjust the DCV potentiometers to correspond to the DCV
voltage output of the indoor air quality sensor at the
user-determined setpoint. See Fig. 75.
57
HIGH LIMIT
CURVE
C06037
turn the enthalpy setpoint
measured in the space
2
IAQ sensor according to