Johnson Controls ZE Series Installation Manual page 41

Table 13: Smart Equipment™ Economizer Board Details (Continued)
Board Cover
Label Label
C COM
PURGE
IN9
24V~
EX VFD
FLT
IN10
24V~
1. When wiring unit and other devices using the SA Bus and FC Bus, see Table 34.
Indoor Air Quality - IAQ
Indoor Air Quality (indoor sensor input): The Indoor Air Quality
sensor is connected to the economizer board through the IAQ
analog input terminal and the associated COM and 24V~ inputs
on the economizer board. Terminal IAQ accepts a 0 to +10 Vdc
signal with respect to the (IAQ) terminal. When the signal is
below its set point, the actuator is allowed to modulate normally
in accordance with the enthalpy and mixed air sensor inputs.
When the IAQ signal exceeds its set point setting, and there is
no call for free cooling, the actuator is proportionately
modulated from the 0 to 10 Vdc signal, with 0 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 its 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 IAQ voltage input.
• Optional CO2 Space Sensor Kit Part #2AQ04700524
• Optional CO2 Sensor Kit Part #2AQ04700624
Phasing
ZE units are properly phased at the factory. Check for proper
compressor rotation. If the blower or compressors rotate in the
wrong direction at start-up, the electrical connection to the unit
is misphased. Change the phasing of the Field Line
Connection at the factory or field supplied disconnect to
obtain proper rotation. (Scroll compressors operate in only one
direction. If the scroll is drawing low amperage, has similar
suction and discharge pressures, or producing a high noise
level, the scroll is misphased.)
Belt Tension
Johnson Controls Ducted Systems
Description
24 VAC common/0-5 VDC negative for the
building pressure sensor
BINARY INPUTS at right on lower edge of economizer board
24 VAC hot input from the PURGE dry contact
24 VAC hot supplied for the purge dry contact
24 VAC hot input from the power Exhaust
Variable Frequency Drive Fault contact
24 VAC hot supplied for the power exhaust
variable frequency drive fault contact
Function & Comments
Connects through circuit trace to 24V~ IN pin COM
Purge parameter reports input status (False with 0 VAC input-
True with 24 VAC input). When Purge status is True, heating and
cooling operation is prevented, the indoor blower and power
exhaust fan operate, the economizer actuator is positioned to
100%.
Connects through circuit trace to 24V~ IN pin HOT
ExFanVFDFlt parameter reports input status (Normal with 0 VAC
input-Alarm with 24 VAC input) when ExFType selection is
Variable Frequency Fan. When ExFanVFDFlt status is Alarm,
EX-FAN fan output is prevented.
Connects through circuit trace to 24V~ IN pin HOT
Scroll compressors require proper rotation to operate
correctly. Units are properly phased at the factory. Do
not change the internal wiring to make the blower
condenser fans, or compressor rotate correctly.
When installing equipment in a facility with a 3 phase
high-leg delta power supply, care must be taken to
ensure that the high-leg conductor is not attached to
either of the two legs of the (single phase, direct drive)
X13 or ECM motors. Failure to do so can result in the
motor acting erratically or not running at all.
Check for the high leg conductor by checking voltage of
each phase to ground.
Example: A or L1 phase to ground, voltage reading is
120V. B or L2 phase to ground, voltage reading is 195 to
208V. C or L3 phase to ground, voltage reading is 120V.
Therefore B or L2 phase is the high Leg. The high
should always be wired to the center or B or L2 tap.
Note: Check all three phase motors and compressors
for proper rotation after making a change. If it is
necessary to change 3 phase motor rotation, swap A or
L1 and C or L3 only.
Blower Rotation
Check for proper supply air blower rotation. If the blower is
rotating backwards, the line voltage at the unit point of power
connection is misphased (See 'PHASING').
The tension on the belt should be adjusted as shown in Figure 20.
6021974-UIM-A-1120
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