Model IGX Make-Up Air
30
®
Typical settings are 0.0 in. wg (0 kPa) for the lower and
0.10 in. wg (0.02 kPa) for the upper pressure setting.
The needle in this photo indicates a negative building
pressure. During correct operation, the indicating needle
will remain between or near the setting needles.
External Signal
A modulating spring return actuator is used to control
the return air amounts. Return air damper modulates
from fully open to fully closed based on an external
2-10 VDC or 4-20 mA signal (by others).
The return air damper will close with a 10 VDC or 20 mA
signal. The return air damper should open with a 2 VDC
or 4mA signal. The damper actuator may take a few
minutes to open or close.
Optional Duct Static Pressure Sensor
The controller will modulate the supply fan based upon
a comparison of the duct static pressure set point to
the actual duct static pressure level reported from the
sensor. Sensor shipped loose.
Optional Building Static Pressure Sensor
The controller will modulate the supply fan based upon
a comparison of the building static pressure set point
to the actual building static pressure level reported from
the sensor. Sensor shipped loose.
Control Voltage
Manufacturer’s standard control voltage is 24 VAC.
Control wire resistance must not exceed 0.75 ohms
(approximately 285 feet total (86.9 m) length for
14 gauge wire; 455 feet (138.7 m) total length for
12 gauge wire). If the resistance exceeds 0.75 ohms,
an industrial-style relay must be wired in place of the
remote switch. The relay must be rated for at least
5 amps and have a 24 VAC coil. Failure to comply with
these guidelines may cause motor starters to chatter or
not pull in, resulting in contactor failures and/or motor
failures.
The recirculation operation option is recommended
when the ventilation equipment provides the primary
source of heating for the space or when exhaust
fan tracking is required. Control strategies include
2-position option and modulating options. During
commissioning, test the recirculation control system.
2-Position Option
A 2-position spring return actuator
is used to control the return air
amounts. The damper moves from
open to closed. If power is cut to
the unit, the outdoor air damper will
fail closed.
Turn the recirculating switch on
the remote control panel to each
position and confirm that the return
air damper adjusts accordingly. The
damper actuator may take a few minutes to open or
close.
Modulating Options
Potentiometer Control
A modulating spring return actuator is
used to control the return air amounts.
The return air damper modulates from
fully open to fully closed based on a
signal from a remote potentiometer.
To test potentiometer operation, turn
the potentiometer to the two extremes.
Confirm that the return air damper
fully opens and fully closes. When
the potentiometer is at minimum, the
return air damper will open. When
the potentiometer is at maximum, the
return air damper will close. The damper actuator may
take a few minutes to open or close.
Building Pressure Control
A floating point spring return actuator
is used to control the return air
amounts. The return air damper
modulates from fully open to fully
closed based on a signal from a
remote pressure sensing device.
On the Photohelic
®
gauge, turn both
knobs to the upper most pressure
setting. You may have to remove the
outdoor pressure tap tubing. The
return air damper should close.
Set both knobs at the lowest setting
and the damper should open. It may take one to two
minutes for the damper to reach the desired position.
Reset the correct pressure limits before starting the unit.
70
65
75
80
85
90
60
55
(OPTIONAL)
BLOWER
DIRTY FIL TERS
MAIN V AL VES
RECIRCULA TION
EXHAUST
SUPPL Y
HEA T
(OPTIONAL)
2-Position
Damper Control
EXHAUST
(OPTIONAL)
(OPTIONAL)
55
60
65
70
75
80
85
90
SUPPLY
HEAT
DIRTY FILTERS
MAIN VALVES
BLOWERS
Potentiometer
Control
70
65
75
80
85
90
60
55
(OPTIONAL)
BLOWER
DIRTY FIL TERS
MAIN V AL VES
EXHAUST
SUPPL Y
HEA T
(OPTIONAL)
PHOTOHELIC
Building Pressure
Control
Start-Up: Indirect Gas-Fired Heating
Optional Features
Recirculation Operation
Photohelic
®
Gauge
Pressure Indicating
Needle
Pressure Setting
Needles
Pressure Setting Knobs
