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Building Freeze Protection
This option is intended to disable the unit supply fan
in the event the discharge temperature falls below
35°F for five minutes. This is accomplished through
electromechanical controls or a microprocessor.
Building freeze protection is selected when the unit may
operate while the space it serves is unoccupied.
Microprocessor Controls
The controller has been pre-programmed to offer
multiple control sequences for providing tempered air.
Easy monitoring and adjustment of unit parameters can
be accomplished by way of the lighted graphical display
and an integral push-button keypad or by way of the
Building Management System (BMS) communication
with the addition of an optional BMS communication
card. This addition allows the user too remotely adjust
set points, view unit status points and alarms. The
sequence parameters are fully adjustable. For additional
information, reference the supplemental Microprocessor
Controller for Make-Up Air Reference Guide for more
information.
Packaged Direct Expansion (PDX)
Cooling Module
The PDX module is a complete package that has
been designed for outdoor installations. The PDX
system in the module is a complete, sealed unit with
compressed R-410A refrigerant. It consists of one or
two compressors, evaporator and condenser coils,
and all other necessary components. Reference the
supplemental Packaged DX Module IOM for more
information.
Dirty Filter Switch
To adjust the switch, the unit must be running with all of
the access doors in place, except for the compartment
where the switch is located. The filters must be clean
and in good condition. The adjusting screw is located
on the top of the switch.
Setscrew (on front of switch) must be manually
adjusted after the system is in operation.
Negative pressure connection is toward
the 'front or top' of the switch. (Senses
pressure on the fan side of filters)
Positive pressure connection is toward the 'back or bottom' of
the switch. (Senses pressure at the inlet side of filters)
1. Open the filter compartment and place a sheet of
plastic or cardboard over 50% of the filter media.
32
Model IGX Make-Up Air
Start-Up: Optional Features
Other
2. Close and secure the filter compartment door.
3. Check to see if there is power at the alert signal
4. If power is present, turn the adjustment screw
5. Open the filter compartment and remove the
6. Close and secure the door and check to make sure
Heating and/or Cooling Inlet Air
Sensor(s)
The heating inlet air sensor locks out heating operation
when the inlet temperature rises above set point (field-
adjustable). The cooling inlet air sensor locks out
cooling when inlet temperature falls below set point
(field-adjustable). These components are located in the
unit's control center. Reference the unit's ladder diagram
for component identification and terminal designation.
Inlet/Outlet Damper End Switch
Provides a damper actuator with an end switch that
is wired into the unit's control center. This will prevent
the supply fan from starting up until the end switch
is proven. Reference the unit's ladder diagram for
component identification and terminal designation.
leads (refer to electrical diagram).
counterclockwise until the power goes off. Turn
slightly clockwise until power comes back on. If
power is not present, turn the adjustment screw
clockwise until the power comes on.
obstructing material.
there is no power at the alert signal leads. The unit is
now ready for operation.
®
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