Install Duct Work
IMPORTANT:
Install duct work in accordance with NFPA 90B and any local
codes.
Connect supply air duct to the flange on top of the electric
furnace. If an isolation connector is used, it must be non-
flammable.
A return air duct system is recommended.
Non-Ducted Return Closet Installation
The electric furnace can be installed in a closet with a false
bottom to form a return air plenum or be installed with a return air
plenum under the electric furnace. Louvers or return air grilles are
field supplied. Local codes may limit application of systems
without a ducted return to single-story buildings.
Install louvers in a closet. Use the free area of louver or grille
to determine the size opening required to provide the free
area for metal louvers or grilles. See "Filter Requirements" for
minimum free area required.
If the free area is not known, assume a 25% free area for
wood or a 75% free area for metal louvers or grilles.
If the return air plenum is used, the return air grille should be
immediately in front of the opening in the plenum to allow for
the free flow of return air.
When not installed in front of the opening, there must be
adequate clearance around the electric furnace to allow for
the free flow of return air.
Filter Specifications
Filters are not supplied with these air handlers. It is the installer's
responsibility to install properly sized filters in accordance with
the "Minimum Filter Requirements Chart."
The filter size is determined by the "Nominal Tons Air
Conditioning & Nominal Airflow" (see chart).
Areas and dimensions shown for cleanable filters are based
on filters rated at 600 ft per minute face velocity.
Typical filter sizes are shown; however, any combination of
filters whose area equals or exceeds the minimum area
shown is satisfactory.
Minimum Filter Requirements Chart
Nominal Tons
Square Inch Surface Area
Air Conditioning
&
Disposable
Nominal Airflow
Filters
Up to 2 Tons
432 sq. in.
800 - 900 CFM
20 in. x 25 in.
2¹⁄₂ Tons
480 sq. in.
900-1000 CFM
20 in. x 30 in.
3 Tons
576 sq. in.
1300 - 1500 CFM
*14 in. x 25 in.
3¹⁄₂ Tons
672 sq. in.
1300 - 1500 CFM
*16 in. x 25 in.
4 Tons
768 sq. in.
1500 - 1700 CFM
*20 in. x 25 in.
5 Tons
960 sq. in.
1900 - 2100 CFM
*20 in. x 30 in.
* 2 disposable filters required for these units
If a central return air filter-grille is used, the electric furnace does
not require a filter.
To install a filter at the electric furnace only, use the following kits:
AEFFLTS-1 Filter Kit for 17.5 in. x 22.5 in. cabinets
AEFFLTM492-1 Filter Kit for 22 in. x 21.5 in. cabinets
AEFFLTL493-1 Filter Kit for 22 in. x 26 in. cabinets
Make Electrical Connections
208/240 Volt Installations
WARNING
Electrical Shock Hazard
Disconnect all power supplies before servicing.
Replace all parts and panels before operating.
Failure to do so can result in death or electrical shock.
1. Disconnect all power supplies.
2. Remove the blower access panel.
3. Route the field supply wires to the electric furnace electrical
connection box.
& Nominal Size
Minimum
Return Air
Cleanable
Free Area
Filters
260 sq. in.
260 sq. in.
15 in. x 20 in.
288 sq. in.
288 sq. in.
14 in. x 25 in.
346 sq. in.
346 sq. in
16 in. x 25 in.
404 sq. in.
404 sq. in.
20 in. x 25 in.
461 sq. in.
461 sq. in.
20 in. x 25 in.
576 sq. in.
576 sq. in.
24 in. x 25 in.
5
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