The included drain trap must be
installed to the dehumidifier. Use
PVC primer and cement to
connect the trap to the drain
outlet on the dehumidifier. The
drain outlet is located near the
On/Off toggle switch.
Note
orientation of trap prior to
cementing.
The high side of the
trap mates with the dehumidifier. The adjustable legs on
the dehumidifier must be disengaged approximately 1
7
⁄
8
”
to accommodate the trap. Loosen nuts before adjusting.
Complete the assembly by piping the trap to a drain. The
trap must be primed with water prior to start-up.
If the dehumidifier is installed in an attic or in an area
where flooding is a potential problem, it should be
installed in a secondary drain pan with a float switch. See
page 12 for float switch wiring.
If hanging the unit, use two unistruts to support the base
on the outside edges of the feet locations. There must
be at least 20” of clearance in front of one of the filter
access doors to allow removal of the filter.
3
DRAIN LINE
HANGING
DUCTING
The Aprilaire Dehumidifier is supplied with two
8” round collars. These are packaged with a drain
trap inside the unit behind the filter access panel.
Secure the collars with Four (4) 1-inch sheet metal
screws (not included). UL approved 8” diameter,
insulated flexible duct is recommended for all
connections. Rigid metal duct may also be used. The
duct should be capable of handling at least 2” w.c.
pressure. All joints and seams must be sealed.
Design airflow for the 1750 is 275 CFM @ 0.6” w.c.,
for the 1770 it is 500 CFM @ 0.8” w.c. This is
equivalent to approximately 70 ft. for the 1750 or
100 ft for the 1770 of 8” duct on the inlet and outlet
side of the dehumidifier. Elbows, turns and the static
pressure of the HVAC equipment will affect the
airflow through the dehumidifier.
•
For optimal moisture removal, airflow should be at or above
275 CFM for the 1750, 500 CFM for the 1770.
•
The total static pressure across the 1750 must not exceed 0.8”
w.c., 1.5” w.c. for the 1770. Check all pressures with the HVAC
fan on.
• The outlet from the dehumidifier to the HVAC supply duct must be
located at least 6” downstream of the cooling coil to prevent air from
pulling moisture from the coil.
• If connected to HVAC ductwork, the dehumidifier inlet must be located
at least 6” upstream of the HVAC system air cleaner. This will prevent
any trapped particulates from being drawn into the dehumidifier.
• If UV Germicidal lamps are installed in the HVAC system, use
appropriate methods to protect the flexible duct from the UV light.
• To further reduce any sound that may be created by air movement,
install at least 5 feet of acoustical flexible duct on the outlet and inlet
of the dehumidifier.
2
1
/
2
”
1
/
2
”
Drain Outlet
Drain Trap
High Side
Low Side
FIGURE 1
90-961
3“ MIN
CLEARANCE FOR
ACCESS PANEL
20” MINUMUM
CLEARANCE FOR FILTER
(EITHER SIDE)
6" MIN CLEARANCE
FOR ACCESS PANEL
FILTER
TOP VIEW
FIGURE 2
90-970
