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Check Operation - VAV Units
(optional)
NOTE
Blower Start-Up, steps 1-5 should be performed
before the blower is run.
NOTE
For maintenance issues associated with variable
frequency drives, consult the drive's manual, supplied
with the unit. The drives are programmed at the
factory and should not need any adjustment during
installation and start-up. For kitchen applications, the
drive may be located either in the kitchen or in the
unit.
Variable Air Volume Operation
The variable air volume (VAV) option is recommended
when a building's exhaust volume may vary. This option
uses a variable frequency drive (VFD) to allow the
make-up air volume to track with the exhaust volume,
providing only the amount of make-up air required.
Control strategies include 2-speed and modulating
operation. Before the unit is left in service, the variable
volume control system should be tested.
2-Speed VFD Operation
A VFD is used on a single speed motor to control air
volumes. The VFD is factory-programmed for two speed
operations. It can be switched to low or high speed from
a remote control panel. Turn the fan speed switch on the
remote control panel to each position and confirm that
the fan speed adjusts accordingly.
ModulatinIIg VFD Operation
Potentiometer Control
A VFD is controlled according to an
input from a remote speed selector
(potentiometer). This unit allows
easy manual adjustment of make-up
air volumes. To test potentiometer
operation, turn the potentiometer
to the two extremes. With variable
volume, make sure the fan goes to
maximum and minimum speed.
When the potentiometer is at 0%,
the fan will be at its minimum speed.
When the potentiometer is at 100%,
the fan will be at its maximum speed.
18
Model IG / IGX Make-Up Air
Building Pressure Control
A VFD is controlled according to an
input from a pressure sensing device.
Turn both device knobs to the upper
most pressure setting. You may have
to remove the outdoor pressure tap
tubing. VAV systems should go to
maximum speed. Set both device
knobs at the lowest setting and the
VAV systems should go to minimum
speed.
Reset the correct pressure limits
before starting the unit.
This picture shows
a typical photohelic
setting. Typical settings
are 0.0 in. wg for the
lower pressure setting
and 0.10 in. wg for the
upper pressure setting.
The needle indicates
a negative building
pressure. During correct
operation, the indicating
needle will remain
between or near the setting
needles.
External Signal
A VFD is controlled according to an input from an
external 2-10 VDC or 4-20 mA signal (by others).
A 2 VDC or 4 mA signal will send the blower to low
speed. The blower will go to maximum speed with a
10 VDC or 20 mA signal.
Variable Kitchen Control
BLOWERS
A VFD is controlled according to an input from a remote
EXHAUST
(OPTIONAL)
speed control. This unit allows automatic adjustment of
SUPPLY
MAIN VALVES
HEAT
make-up air volumes based on varying cooking loads.
Microprocessor
DIRTY FILTERS
70
75
If the optional
65
80
(OPTIONAL)
60
85
55
90
microprocessor is mounted
in the control center of the
unit, it may be configured to
control the VFD.
Potentiometer
Control
Similar control hardware is used for the network
interfacing control. Only the microprocessor controller
will contain keypad buttons on both the left and right
side of the display. For any other hardware, please
reference the Check Operation section. If the make-
up air unit has been supplied with the microprocessor
controller, additional information can be found by
referencing the Microprocessor Controller Installation,
Operation and Maintenance Manual.
EXHAUST
(OPTIONAL)
SUPPL Y
MAIN V AL VES
HEA T
DIRTY FIL TERS
70
75
65
80
60
85
55
90
PHOTOHELIC
Building
Pressure Control
Pressure
Pressure Setting
Indicating Needle
Needles
Pressure Setting Knobs
Photohelic Gauge
NOTE
BLOWER
(OPTIONAL)
®
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