Trane Voyager Commercial Installation, Operation And Maintenance Manual page 54

S S t t a a r r t t u u p p
Figure 41. SZVAV DCV with OA CFM
compensation
Design @ Minimum Fan Speed
(RTVM R130)
OAD
Posi on
Setpoints
Design @ Middle Fan Speed
(RTVM R136)
OAD Target
Setpoint
Design @ Full Fan Speed
DCV @ Minimum Fan Speed
(RTEM Design Min.)
(RTVM R41)
DCV @ Full Fan Speed
Minimum Fan Speed
Units with Traq Sensor
The outside air enters the unit through the Traq Sensor
assembly and is measured by velocity pressure flow
rings. The velocity pressure flow rings are connected to
a pressure transducer/solenoid assembly.The solenoid
is used for calibration purposes to compensate for
temperature swings that could affect the transducer.
The ReliaTel Ventilation Module (RTVM) utilizes the
velocity pressure input, the outdoor air temperature
input, and the minimum outside air CFM setpoint to
modify the volume (CFM) of outside air entering the
unit as the measured airflow deviates from setpoint.
For units with Traq, when the optional CO
installed and Demand Controlled Ventilation is enabled
the Minimum Outside Air CFM Setpoint will be
adjusted linearly between two airflow setpoints, the
Design Minimum Outside Air (OA) CFM Setpoint (R130)
and the DCV Minimum Outside Air CFM (OA) Setpoint
(R41). The resulting calculated setpoint is the Minimum
OA CFM Target which is the setpoint used for active
airflow control. The Minimum OA CFM Target Setpoint
will vary proportionally between the DCV Minimum OA
Flow CFM Setpoint and the Design Minimum OA CFM
Setpoint as CO varies between the CO
2
Setpoint and the CO Upper Limit Setpoint as shown in
2
the following figure. The CO
RTEM as with normal DCV control without Traq option.
54
Corresponds to Design
CO2 (DCV UL) Setpoint
Increasing CO2
Corresponds to DCV CO2 (DCV
LL) Setpoint
Middle Fan Speed Full Fan Speed
sensor is
2
Lower Limit
2
setpoints are set on the
2
Figure 42. Minimum outside air CFM setpoint
Outside Air Damper Minimum Positions
without DCV
For units not configured with DCV (no CO
value available), additional minimum position
setpoints to increase outdoor airflow accuracy will be
supported. The operation will be similar to OA CFM
Compensation on Traditional VAV units with the
addition of a Design Minimum Position setpoint at
Middle Fan Speed Command. The following setpoint
potentiometers will be used on the RTEM:
• Design Min at Minimum Fan Speed Command
(RTEM DCV Min)
• Design Min at Middle Fan Speed Command (RTEM
DCV Setpoint LL)
• Design Min at Full Fan Speed Command (RTEM
Design Min)
The controller will calculate the active OA Damper
Minimum position linearly between the user-selected
setpoints based on the supply fan speed command.
The range for the Design Min setpoints at Minimum
and Middle Fan Speed Command will be 0-100% while
the range for the Design Min at Full Fan Speed
Command setpoint will be 0-50%.
By default, the Design Minimum Position schedule (red
line below) will be a linear line through all user
selectable Design Minimum Position setpoints. As with
Demand Controlled Ventilation, if the Design Minimum
Position at Middle fan speed command is set to a point
that would be higher than the calculated linear line
between the Design Minimum Position setpoints at
Minimum and Maximum fan speed command, the
minimum position will be limited to the point that
would make the Design Minimum Position schedule
linear.
Provisions have been made in Service Test Mode to
allow for proper damper minimum position setup:
• To set the Design Minimum Position setpoint at
Minimum Fan Speed, set the unit to operate at Step
sensor
2
RT-SVX34R-EN