fIGURE 3 – Install Damper in Collar
90-1503
fIGURE 4 – Install Collar with Damper on Outlet
90-1503
fIGURE 5 – Minimum Ductwork bend Distance
90-1503
DUCT COllARS & bACKflOW DAMPER
The backflow damper installs on the outlet side of the dehumidifier, using features molded
into the duct collar .
1 . Remove the duct collars and backflow damper from the inner pack .
2 . Place the backflow damper in the collar with the damper pivot shaft resting in the slot in
the collar (see
figure 3
) .
3 . Position the collar and damper with damper pivot shaft up and install on the outlet panel
using four #8 x 1” field supplied sheet metal screws (see
figure 4
) . The collar should sit
flush on the outlet panel and secure the backflow damper .
4 . Verify that the damper swings freely by lifting up on the damper and allowing it to
swing closed .
5 . Make sure there are no bends in the ductwork coming off the outlet for a minimum of 4” .
This will ensure that the ductwork will not interfere with backflow damper function
(see
figure 5
) .
MECHANICAl INSTAllATION
INLET
OUTLET
4" MIN.
BACKFLOW
DAMPER
CAUTION
Only install
damper on outlet.
Dehumidifier will
not function if
damper is installed
on inlet.
GENERAl DUCTWORK RECOMMENDATIONS
• When ducted to the HVAC supply, the outlet from the dehumidifier
must be located at least 6” downstream of the cooling coil to
prevent outlet air from pulling moisture from the coil .
• To minimize sound from air movement and vibration, install 5 feet
minimum of flex duct on the inlet and outlet of the dehumidifier .
• Use the least amount of ductwork possible. UL approved, insulated
duct is recommended for all connections .
• Use insulated duct for ventilation.
TAblE 2 – Maximum Duct lengths
1750A
1770A
CFM
250
500
External Static Pressure
0 .6”w .c .
0 .9”w .c .
Amount of Ducting
8” dia ., 70 ft .
10” dia ., 350 ft .
Notes:
1 . Duct length totals include both inlet and outlet sides .
2 . Elbows, turns, and the static pressure of the HVAC equipment
will affect the airflow through the dehumidifier .
3 . Maximum duct length recommendation assumes 0 .2” w .c .
pressure increase due to filter loading . Maintenance of filter is
important to maintain airflow .
4 . Ductwork to be installed in accordance with SMACNA Standards .
5 . Duct size recommendations based on maximum velocity of 900
FPM inside of duct .
5
