Ventilation Control - Trane Voyager Commercial Installation, Operation And Maintenance Manual

Table 30. OA flow adjustment setpoint (continued)
OA Flow
Voltage
Adjustment
Reading
(R136)
Multiplier/
Vdc
Adjustment
0.96 1.1
0.97 1.18
0.98 1.22
0.99 1.25
1 1.3 - 1.84
1.01 1.86
1.02 1.89
1.03 1.92
1.04 1.96
1.05 2
1.06 2.03
1.07 2.06
1.08 2.1
1.09 2.12
1.1 2.14
1.11 2.16
1.12 2.18
1.13 2.2
1.14 2.24
1.15 2.26
1.16 2.28
1.17 2.3
1.18 2.34
1.19 2.36
1.2 2.4

Ventilation Control

Units configured for Single Zone VAV control require
special handling of the OA Damper Minimum Position
control in order to compensate for the non-linearity of
airflow associated with the variable supply fan speed
and damper combinations.
Demand Controlled Ventilation
Units configured for SZVAV and Demand Controlled
Ventilation (CO sensor value available) require a new
2
control scheme comprised of 2 existing schemes that
have been traditionally mutually exclusive; DCV and
OA CFM Compensation.
Units configured with DCV will invoke the new Demand
Controlled Ventilation scheme which allows variable
Bldg. Design and DCV Minimum Positions and OA
Damper Position Target setpoints based on the supply
fan speed and space CO
2
This new scheme will require the setting of 5 OA
Damper position setpoints; 3 more than on non-SZ
VAV. These new setpoints are located on the RTVM
module:
• Design Min Position @ Minimum Fan Speed
Command (RTVM R130)
• Design Min Position @ Middle Fan Speed
Command (RTVM R136)
RT-SVX34R-EN
requirements.
• Design Min Position @ Full Fan Speed Command
(RTEM Design Min Position)
• DCV Min Position @ Minimum Fan Speed
Command (RTVM R41)
• DCV Min position @ Full Fan Speed Command
(RTEM DCV Min Position)
As the supply fan speed command varies between
minimum and maximum, the Building Design and DCV
Minimum Position Targets will be calculated linearly
between the user selected setpoints based on the
instantaneous supply fan speed. The Bldg. Design and
DCV Minimum Position Targets will be used to
calculate the Active OA Damper Minimum Position
Target, as on traditional units, based on the Space CO
relative to the active Design and DCV CO
Refer to Figure 41, p. 54 for additional details on the
design.
The Design Minimum and DCV Minimum OA Damper
Position setpoints at Minimum Fan Speed Command
and the Design Minimum OA Damper Position setpoint
at Middle Fan Speed Command will have a range of 0-
100% while the Design Minimum and DCV Minimum
OA Damper Position setpoints at Full fan speed will
have a range of 0-50%. Note that as on non-Single
Zone VAV units, a 10% offset will be enforced between
the Design and DCV Minimum Positions throughout
the fan speed range.
By default, the Design Minimum Position schedule (red
line below) will be a linear line through all user
selectable Design Minimum Position setpoints. The
user will have the ability to set the Design Minimum
Position at Middle fan speed command to a point that
would be lower than the calculated linear line between
the Design Minimum Position setpoints at 0% and
100% fan speed command in order to compensate for
the non-linear outside airflow through the fan and
damper modulation range. However, 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 Full 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 and DCV Minimum Position
setpoints at Minimum Fan Speed, set the unit to
operate at Step 1 (Fan ON) or Step 2 (Economizer
Open) and make the proper adjustments.
• To set the Design Minimum Position setpoint at
Middle Fan Speed, set the unit to operate at Step 3
(Cool 1) and make the proper adjustment.
• To set the Design and DCV Minimum Position
setpoints at Full Fan Speed, set the unit to operate
at Step 4 (Cool 2) and make the proper adjustments.
S S t t a a r r t t u u p p
2
setpoints.
2
53