Page 46
IX--VAV System
Units contain a supply air blower equipped with a variable
frequency drive A96 (VFD) which varies supply air CFM.
The supply air VFD (A96) is located in the control area. See
figure 26.
A-Start-Up
1. A pressure transducer (A30) is shipped in a box in the
blower compartment. Install the transducer according
to manufacturer's instructions.
Note - Make sure the transducer is installed in the main duct
at least 2/3 of the distance away from the unit.
2. Two twisted pairs of shielded cable must be used to
connect the pressure transducer. See figure 25.
J/P378 connector is hanging in the control box.
3. Open all zone dampers and/or boxes.
4. Locate the A55 Unit Controller. Refer to figure 26.
5. Use the mobile service app to calibrate the blower
CFM. Select this menu to start the blower:
SETUP > TEST & BALANCE > BLOWER
The mobile app will display the percent of blower
speed. Adjust blower speed percentage to meet design
airflow specifications. Allow blower speed to stabilize.
6. Press NEXT and follow the instructions to calibrate
static pressure. If the static pressure meets the de
sign specification, press NEXT again to set the set
point. If the static pressure does not meet the design
specification, adjust the pressure and press NEXT to
set the setpoint.
7. Record new setpoints in table 22.
TABLE 22
RECORD ADJUSTED SETPOINTS
Parameter
Setpoint
Description
Setpoint
“w.c.
Display
Setting
386 Smoke
387 Ventilation
388 Heating
389 Cooling
PRESSURE TRANSDUCER WIRING
TWISTED
PAIR
UNUSED WIRE
DRAIN
NOT
CONNECTED
NOT
CONNECTED
TWISTED
PAIR
FIGURE 25
A30
+S
_
+
P378
1
2
3
Note - The Unit Controller will lock-out the unit for 5 minutes
if static pressure exceeds 2.0”w.c. for 20 seconds. The Unit
Controller will permanently shut down the unit after three
occurrences. See mobile service app parameters 110, 42,
and 43 to adjust default values.
8. If the desired CFM cannot be met with current pulley
setup, refer to the Blower Operation and Adjustments
section to adjust CFM.
FIGURE 26
CONTROL AREA
A96
SUPPLY AIR VFD
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