Page 30
LGM/LCM156, 180, 210, 240, 300
Variable Air Volume Start-Up
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 32.
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 31.
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 32.
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
design specification, press NEXT again to set the
setpoint. 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 17.
TABLE 17
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 31
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 32
CONTROL AREA
A96
SUPPLY AIR VFD
