Trane Technologies Voyager 3 - Economizer Damper Adjustment; Economizer (O;A) Dampers

RT-SVX34V-EN
51
Figure 39. (Upflow) Exhaust maximum damper
position
Less Exhaust
More Exhaust
Figure 40. (Horizontal) Exhaust maximum damper
position
Less Exhaust
More Exhaust
Economizer Damper Adjustment
Economizer (O/A) Dampers
Arbitrarily adjusting the outside air dampers to open fully
when the return air dampers are fully closed can overload
the supply fan motor or deliver higher CFM to the space
than designed. This causes higher operating 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 41, p. 51 illustrates the damper
assembly and through 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” 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 through .
4. Set the drive rod swivel to the appropriate hole
according to through . The units are shipped using hole
“A” with no reference to any specific operating
condition.
Figure 41. Economizer (O/A) damper assembly
Table 23. 27.5 - 35 Ton downflow economizer (O/A) damper static pressure setup
System
Design CFM
Return Air Duct Static + Return Air Damper Static (Inches of Water)
0.2 0.4 0.6 0.8 1 1.2 1.4
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
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
Startup