518676-BIM-C-0610
Johnson Controls Unitary Products
37
Enthalpy Set Point Adjustment
• The enthalpy set point may now be set by selecting the
desired set point shown in the Enthalpy Set Point
Adjustment Figure 27. Adjust as follows:
• For a single enthalpy operation carefully turn the set point
adjusting screw (found on the damper control module) to
the "A", "B", "C" or "D" setting corresponding to the lettered
curve of the Enthalpy Set Point Adjustment Figure 28.
• For a dual enthalpy operation, carefully turn the set point
adjusting screw fully clockwise past the "D" setting.
Power Exhaust Damper Set Point (With Or Without Power
Exhaust)
• With no power exhaust option, adjust the Exhaust Air
Adjustment Screw fully clockwise. This will allow 2nd
stage cooling to operate.
• With power exhaust option, each building pressurization
requirement will be different. The point at which the power
exhaust comes on is determined by the economizer
damper position (Percent Open). The Exhaust Air
Adjustment Screw should be set at the Percent Open of
the economizer damper at which the power exhaust is
needed. It can be set from 0 to 100% damper open.
Indoor Air Quality AQ
Indoor Air Quality (indoor sensor input): Terminal AQ accepts a
+2 to +10 Vdc signal with respect to the (AQ1) terminal. When
the signal is below it's set point, the actuator is allowed to
modulate normally in accordance with the enthalpy and mixed
air sensor inputs. When the AQ signal exceeds it's set point
setting and there is no call for free cooling, the actuator is
proportionately modulated from the 2 to 10 Vdc signal, with 2
Vdc corresponding to full closed and 10 Vdc corresponding to
full open. When there is no call for free cooling, the damper
position is limited by the IAQ Max damper position setting.
When the signal exceeds it's set point (Demand Control
Ventilation Set Point) setting and there is a call for free cooling,
the actuator modulates from the minimum position to the full
open position based on the highest call from either the mixed
air sensor input or the AQ voltage input.
• Optional CO
2
Space Sensor Kit Part # 2AQ04700324
• Optional CO
2
Sensor Kit Part # 2AQ04700424
Replace the top rear access panel on the unit.
Figure 27: Enthalpy Set Point Chart
40
(4)
70
(21)
50
(10)
55
(13)
60
(16)
65
(18)
35
(2)
45
(7)
75
(24)
80
(27)
35
(2)
40
(4)
45
(7)
50
(10)
55
(13)
60
(16)
65
(18)
70
(21)
75
(24)
80
(27)
85
(29)
85
(29)
90
(32)
90
(32)
105
(41)
110
(43)
100
(38)
95
(35)
95
(35)
100
(38)
105
(41)
110
(43)
APPROXIMATE DRY BULB TEMPERATURE -
0
F (
0
C)
D
D
C
C
B
B
A
A
CONTROL
CURVE
CONTROL POINT
APPROX.
0
F (
0
C)
AT 50% RH
A
D
C
B
63 (17)
73 (23)
70 (21)
67 (19)
