Unit installation

Controls
68 SCXF-SVX01K-EN
BACnet
®
Communications Interface
(BCI-I) Module
The BACnet
®
Communication Interface for IntelliPak self-
contained (BCI-I) controller expands communications
from the unit UCM network toTracer SC or a 3rd party
building automation system, utilizing BACnet, and allows
external setpoint and configuration adjustment and
monitoring of status and diagnostics.The BCI-I utilizes the
BACnet defined MS/TP protocol as defined in ASHRAE
standard135-2004. This controller works in standalone
mode, withTracer SC or when connected to a 3rdparty
building automation system that supports BACnet.
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 40, p. 68 for humidity vs. voltage values.
Ventilation Control Module (VCM)
(Available only withTraq™ 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 41,
p. 68 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 CO2 sensor can be connected to the
VCM to control CO2 reset.The reset function adjusts the
minimum cfm upward as the CO2 concentrations increase.
The maximum effective (reset) setpoint value for fresh air
entering the unit is limited to the system’s operating cfm.
Table 43, p. 69 lists the minimum outside air cfm vs. input
voltage.
Figure 40. Relative humidity vs. voltage
Figure 41. Velocity pressure transducer/solenoid assembly
Tube from low side
of Transducer
Pressure
Transducer
Ventilation
Control Module
Solenoid
Tube from high side
of Transducer
Tube from low side
of Velocity Ring