64 SCXF-SVX01B-EN
Figure O-GI-2. Velocity Pressure Trans-
ducer/Solenoid Assembly.
PURGE sequence “D”
This sequence can purge the air out of a
building before coming out of unoccupied
mode of operation in a VAV system. Also,
it can be used to purge smoke or stale air.
• Supply fan – on
• Supply fan VFD – on (60 Hz)
• Inlet guide vanes/VAV boxes – Open
• Outside air damper – Open
• Heat – all stages – Off, Modulating heat
output at 0 vdc
• Occupied/Unoccupied output –
Energized
• VO relay – Energized
• Exhaust fan (field-installed) - On
• Exhaust damper (field-installed) - Open
PURGE with duct pressure control “E”
This sequence can be used when supply
air control is required for smoke control.
• Supply fan – on
• Supply fan VFD – on (if equipped)
• Inlet guide vanes – controlled by supply
air pressure control function with
supply air pressure high limit disabled
• Outside air dampers – open
• Heat – all stages – off, hydronic heat
output at 0 vdc
• Occupied/unoccupied output – energized
• VO relay – energized
• Exhaust fan (field-installed) - on
• Exhaust damper (field-installed) - open
Note: Each system (cooling, exhaust,
supply air, etc.) within the unit can be
redefined in the field for each of the five
sequences, if required. Also the definitions
of any or all of the five sequences may be
locked into the software by simple key
strokes at the human interface panel. Once
locked into the software, the sequences
cannot be changed.
Trane Communications
Interface (TCI ) Module - Option
used with Trane ICS
TM
The Trane communication interface
module allows external setpoints for
most of the unit functions to be
communicated to the unit's UCM network
via a Trane ICS
TM
systems. DIP switch
settings on the TCI module for this
application are; switches 1, 2, and 3 “off.”
For a Summit
TM
system, the DIP switch
settings are; switch 1 “off,” 2 “on,” and 3
“off.”
Owner
General
Information
Exhaust/Comparative
Enthalpy (ECEM ) Module -
Option used on units with
comparative enthalpy option
The exhaust/comparative enthalpy
module receives information from the
return air humidity sensor, and the RTM
outside air temperature sensor and
outside air humidity sensor, the outside
air humidity sensor and temperature
sensor to utilize the lowest possible
enthalpy level when considering
economizer operation. In addition, it
receives space pressure information to
maintain the space pressure within the
setpoint control band. Refer to the Figure
O-GI-1 for humidity vs. voltage values.
Ventilation Control Module
(VCM) - Available only with
Tra q ™ Damper Option
The ventilation control module (VCM) is
located in the airside economizer section
of the unit and linked to the unit’s UCM
network. Using a velocity pressure
transducer/solenoid (pressure sensing
ring) in the fresh air section allows the
VCM to monitor and control fresh air
entering the unit to a minimum airflow
setpoint. See Figure O-GI-2 for a detail
view of the velocity pressure transducer/
solenoid assembly.
An optional temperature sensor can be
connected to the VCM to enable control
of a field installed fresh air preheater.
Also, a field-provided CO
2
sensor can be
connected to the VCM to control CO
2
reset. The reset function adjusts the
minimum cfm upward as the CO
2
concentrations increase. The maximum
effective (reset) setpoint value for fresh
air entering the unit is limited to the
system’s operating cfm. Table O-GI-5 lists
the minimum outside air cfm vs. input
voltage.
Table O-GI-5. Minimum Outside Air
Setpoint w/VCM Module and Traq™
Sensing.
Unit Input Volts CFM
SXWF 20 0.5 - 4.5 vdc 6,325-8,500
SXWF 22 0.5 - 4.5 vdc 6,325-9,350
SXWF 25 0.5 - 4.5 vdc 6,500-10,625
SXWF 29 0.5 - 4.5 vdc 8,700-12,325
SXWF 32 0.5 - 4.5 vdc 8,700-13,600
SXWF 35 0.5 - 4.5 vdc 9,100-14,875
SXWF 38 0.5 - 4.5 vdc 9,880-16,150
SXWF 42 0.5 - 4.5 vdc 11,200-17,859
SXWF 46 0.5 - 4.5 vdc 11,960-19,550
SXWF 52 0.5 - 4.5 vdc 14,250-22,100
SXWF 58 0.5 - 4.5 vdc 15,080-24,650
SXWF 65 0.5 - 4.5 vdc 16,900-27,625
SXWF 72 0.5 - 4.5 vdc 18,700-29,800
SXWF 80 0.5 - 4.5 vdc 20,800-29,800
SXRF 20 0.5 - 4.5 vdc 6,500-10,625
SXRF 25 0.5 - 4.5 vdc 8,700-12,325
SXRF 29 0.5 - 4.5 vdc 8,700-13,600
SXRF 30 0.5 - 4.5 vdc 9,100-14,875
SXRF 35 0.5 - 4.5 vdc 9,880-16,150
SXRF 40 0.5 - 4.5 vdc 11,960-19,550
SXRF 50 0.5 - 4.5 vdc 15,080-24,650
SXRF 60 0.5 - 4.5 vdc 20,800-29,800
Figure O-GI-1. ECEM Relative Humidity vs.
Voltage.
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0 102030405060708090100
Percent Relative Humidity
Volts
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