4
Attaching Power Exhaust to the Return Air Duct:
1. Make sure all power exhaust harnesses are
connected as indicated in the previous steps.
2. Make sure all wiring is secure. Use field-supplied wire
ties if necessary. Be sure that wiring does not interfere
with operation of the HVAC unit, economizer, or power
exhaust.
3. Apply gasket from hardware bag to the mating flanges
of the power exhaust. (Fig. 6)
4. Lift power exhaust and install over the duct opening
using the #10 x 3/4in. long screws provided. (Fig 6).
Make sure wiring harnesses are properly secured.
GASKET AROUND FLANGE
SHEETMETAL SCREWS
Figure 6 – Power Exhaust Installed on Duct
5. Return power to unit and remove lockout tag. For gas
units, turn on the gas supply.
6. Test power exhaust operation by setting the power
exhaust set point on the economizer controller to 0%.
Power exhaust performance is shown in Fig 7.
0
1000
2000
3000
4000
5000
0.1
0.2
0.3
0.4
0.5
EX
HA
UST
A
IR
FL
OW
(c
fm
)
RETURN DUCT STATIC PRESSURE (in wc)
3 to 6 Ton Units
208/230V
3 to 6 Ton Units
460V
7½ to 12½ Ton Units
208/230V
7½ to 12½ Ton Units
460V
Figure 7 – Power Exhaust Performance
7. Adjust the power exhaust set point on the economizer
controller to the desired activation point per unit
schematic.
