51
DIFFERENTIAL ENTHALPY CONTROL
For differential enthalpy control, the EconoMi$er IV controller
uses two enthalpy sensors (HH57AC078 and CRENT-
DIF004A00), one in the outside air and one in the return air duct.
The EconoMi$er IV controller compares 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. 75. Mount the return air enthalpy sensor in the return air duct.
See Fig. 74. Wiring is provided in the EconoMi$er IV wiring har-
ness. See Fig. 67. The outdoor enthalpy changeover set point is set
with the outdoor enthalpy set point potentiometer on the
EconoMi$er IV controller. When using this mode of changeover
control, turn the enthalpy set point potentiometer fully clockwise
to the D setting.
Fig. 76 — Enthalpy Changeover Set Points
INDOOR AIR QUALITY (IAQ) SENSOR INPUT
The IAQ input can be used for demand controlled ventilation con-
trol based on the level of CO
2
measured in the space or return air
duct.
Mount the accessory IAQ sensor according to manufacturer speci-
fications. The IAQ sensor should be wired to the AQ and AQ1 ter-
minals of the controller. Adjust the DCV potentiometers to corre-
spond to the DCV voltage output of the indoor air quality sensor at
the user-determined set point. See Fig. 77.
Fig. 77 — CO
2
Sensor Maximum Range Settings
If a separate field-supplied transformer is used to power the IAQ
sensor, the sensor must not be grounded or the EconoMi$er IV
control board will be damaged.
When using demand ventilation, the minimum damper position
represents the minimum ventilation position for VOC (volatile or-
ganic compounds) ventilation requirements. The maximum de-
mand ventilation position is used for fully occupied ventilation.
When demand ventilation control is not being used, the minimum
position potentiometer should be used to set the occupied ventila-
tion position. The maximum demand ventilation position should
be turned fully clockwise.
EXHAUST SET POINT ADJUSTMENT
The exhaust set point will determine when the exhaust fan runs
based on damper position (if accessory power exhaust is in-
stalled). The set point is modified with the Exhaust Fan set point
(EXH SET) potentiometer. See Fig. 71. The set point represents
the damper position above which the exhaust fans will be turned
on. When there is a call for exhaust, the EconoMi$er IV controller
provides a 45 ± 15 second delay before exhaust fan activation to
allow the dampers to open. This delay allows the damper to reach
the appropriate position to avoid unnecessary fan overload.
MINIMUM POSITION CONTROL
There is a minimum damper position potentiometer on the
EconoMi$er IV controller. See Fig. 71. The minimum damper po-
sition maintains the minimum airflow into the building during the
occupied period.
When using demand ventilation, the minimum damper position
represents the minimum ventilation position for Volatile Organic
Compound (VOC) ventilation requirements. The maximum de-
mand ventilation position is used for fully occupied ventilation.
When demand ventilation control is not being used, the minimum
position potentiometer should be used to set the occupied ventila-
tion position. The maximum demand ventilation position should
be turned fully clockwise.
Adjust the minimum position potentiometer to allow the mini-
mum amount of outdoor air, as required by local codes, to enter
the building. Make minimum position adjustments with at least
10°F temperature difference between the outdoor and return-air
temperatures.
CONTROL
CURVE
A
B
C
D
CONTROL POINT
APPROX.
deg. F (deg. C)
AT 50
%
RH
73 (23)
70 (21)
67 (19)
63 (17)
12
14
16
1
8
20
2
2
2
4
2
6
28
30
32
3
4
3
6
38
40
42
4
4
46
9
0
1
0
0
80
7
0
60
50
40
30
20
10
E
NTHALPY
BTU PER
POUN
D DRY
AI
R
85
(29)
90
(32)
95
(35)
100
(38)
105
(41)
110
(43)
3
5
(2)
35
(2)
40
(4)
40
(4)
105
(41)
110
(43)
45
(7)
45
(7)
50
(10)
50
(10)
55
(13)
55
(13)
60
(16)
60
(16)
65
(18)
65
(18)
70
(21)
70
(21)
75
(24)
75
(24)
80
(27)
80
(27)
85
(29)
90
(32)
95
(35)
100
(38)
A
A
B
B
C
C
D
D
RELA
TI
VE HUMI
DI
TY (
%
)
HIGH LIMIT
CURVE
APPROXIMATE DRY BULB TEMPERATURE--degree
s
F (degree
s
C)
0
1000
2000
3
000
4000
5000
6000
2
3
4
5
6
7
8
RANGE
C
ONFIGURA
TION
(ppm)
DAMPER VOLTAGE FOR MAX VENTILATION RATE
CO
S
EN
S
OR MAX RANGE
S
ETTING
2
8
00 ppm
900 ppm
1000 ppm
1100 ppm
Summary of Contents for WeatherMaster 48HC04 Series
Page 37: ...37 Fig 60 Integrated Gas Control IGC Board RED LED STATUS ...
Page 45: ...45 Fig 65 RTU Open Overlay for Economizer Wiring ...
Page 46: ...46 Fig 66 VFD Overlay for W2770 Controller Wiring ...
Page 98: ...98 Fig E 48HC A07 YAC Control Diagram 208 230 3 60 460 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 100: ...100 Fig G 48HC D11YAC Control Diagram 208 230 3 60 460 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 101: ...101 Fig H 48HC D12 YAC Control Diagram 208 230 3 60 460 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 102: ...102 Fig I 48HC A04 A06 YAC Power Diagram 208 230 1 60 APPENDIX D WIRING DIAGRAMS ...
Page 103: ...103 Fig J 48HC A04 A06 YAC Power Diagram 208 230 3 60 460 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 104: ...104 Fig K 48HC A04 A06 YAC Power Diagram 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 107: ...107 Fig N 48HC A07 A12 YAC Power Diagram 208 230 3 60 460 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 108: ...108 Fig O 48HC A07 A12 YAC Power Diagram 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 109: ...109 Fig P 48HC D08 D09 YAC Power Diagram 230 460 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 110: ...110 Fig Q 48HC D08 D09 YAC Power Diagram 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 111: ...111 Fig R 48HC D11 YAC Power Diagram 208 230 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 112: ...112 Fig S 48HC D11 YAC Power Diagram 460 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 113: ...113 Fig T 48HC D11 YAC Power Diagram 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 114: ...114 Fig U 48HC D12 YAC Power Diagram 230 460 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 115: ...115 Fig V 48HC D12 YAC Power Diagram 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 116: ...116 Fig W 48HC D14 YAC Control Diagram 208 230 3 60 460 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 117: ...117 Fig X 48HC D14 YAC Power Diagram 208 230 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 118: ...118 Fig Y 48HC D14 YAC Power Diagram 460 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 119: ...119 Fig Z 48HC D14 YAC Power Diagram 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 142: ...142 Fig AW PremierLink System Control Wiring Diagram System APPENDIX D WIRING DIAGRAMS ...
Page 144: ...144 Fig AY RTU Open Wiring Diagram APPENDIX D WIRING DIAGRAMS ...