Trane Voyager Commercial, Installation, Operation And Maintenance Manual

Page: 85 / 156

RT-SVX34R-EN 85
duct static pressures and over pressurization of the
space when the unit is operating in the “economizer”
mode.
The purpose of adjusting the amount of O/A damper
travel is to maintain a balance or equal pressure
between the
O/A dampers and the pressure drop of the return air
system. For models with standard or low-leak
economizers, the O/A and R/A damper linkage is
attached to a plate with a series of holes that allows the
installer or operator to modify the O/A damper travel to
compensate for various RA duct losses.
Figure 58, p. 85
illustrates the damper assembly and Table 57, p. 85
through Table 60, p. 86 list the various damper
positions based on the air flow (CFM) and the return
duct losses (static pressure) for Downflow and
Horizontal units.
To adjust the O/A damper for the correct pressure drop:
1. Measure the return duct static pressure.
2. Enter the calculated CFM from the previous section
“Verifying Proper Airflow” Table 47, p. 78 to obtain
the return air damper pressure drop.
3. Add the measured return duct static pressure and
the return air damper pressure drop together to
obtain the Total Return Static Pressure. Apply this
calculation and the calculated CFM to the
appropriate
Table 57, p. 85 through Table 60, p. 86 .
4. Set the drive rod swivel to the appropriate hole
according to Table 57, p. 85 through Table 60, p.
86 . The units are shipped using hole “A” with no
reference to any specific operating condition.
Figure 58. Economizer (O/A) damper assembly
Table 57. 27.5 - 35 Ton downflow economizer (O/A)
damper static pressure setup
Sys-
tem
De-
sign
CFM
Return Air Duct Return Air Damper
Static (Inches of Water)
0.2-
0
0.4-
0
0.6-
0
0.8-
0
1.0-
0
1.2-
0
1.4-
0
Drive Rod Position
8000 B E E E E E E
8500 B D E E E E E
9500 A C E E E E E
Table 57. 27.5 - 35 Ton downflow economizer (O/A)
damper static pressure setup (continued)
Sys-
tem
De-
sign
CFM
Return Air Duct Return Air Damper
Static (Inches of Water)
0.2-
0
0.4-
0
0.6-
0
0.8-
0
1.0-
0
1.2-
0
1.4-
0
Drive Rod Position
10000 A C D E E E E
10500 A C D E E E E
11000 A B D D E E E
11500 A B C D E E E
12000 A A C D E E E
12500 A A C D D E E
13000 A A B B C D E
Table 58. 27.5 - 35 Ton horizontal economizer (O/A)
damper static pressure setup
Sys-
tem
De-
sign
CFM
Return Air Duct Return Air Damper
Static (Inches of Water)
0.2-
0
0.4-
0
0.6-
0
0.8-
0
1.0-
0
1.2-
0
1.4-
0
Drive Rod Position
8000 A F G G G G G
8500 A F G G G G G
9000 A E G G G G G
9500 A E F G G G G
10000 A D E G G G G
11000 A D E F G G G
11500 A B E F G G G
12000 A A D F G G G
12500 A A D E F G G
13000 A A D E F G G
13500 A A C E F F G
14000 A A C D E F G
14500 A A B D E F F
S Stta arrttu up p