5
5. UNIT LOCATION
The furnace shall be appropriately located to the supply and
return air distribution system. (See “AIR DISTRIBUTION”,
Page 7) Sides and back of the furnace may be enclosed by
wall framing. (See “Minimum Clearances,” Table 4, and
Figures 2 through 5.)
The furnace installation is only intended for free air return
through the furnace door louvers. DO NOT connect a ducted
return air system directly to the furnace. Improper installation
may create a hazard and damage equipment, as well as void
all warranties.
Furnace may be installed on combustible flooring when using
NORDYNE Duct Connectors (see Table 7 and Figures 9-16).
6. MINIMUM CLEARANCES
This heating appliance must be installed with clearances not
less than the minimums shown in Table 4. This heating
appliance must be installed with ample clearance for easy
access to the air filter, blower assembly, burner assembly,
controls, and vent connections.
a. Alcove installations (see Figure 2): minimum 18"
clearance at front of furnace shall be provided for future
servicing. A removable access panel should be installed
between top of the furnace door frame and the ceiling.
b. Closet installations must use a louvered door having a
minimum free area of 235 sq. in. when located 6" from
furnace (See Figure 3). For special clearance between
1" and 6", requirements are a louvered door with a
minimum of 250 sq. in. free area, with the openings in
the closet door directly in line with the louvered openings
in the furnace door . A fully louvered closet door may
be used (See Figure 4).
Figure 1. Overall Dimensions
“A”- 56"
23 3/4"
“B”- 76"
19 3/4"
“A” Model-
w/o Coil Cabinet
“B” Model-
w/Coil Cabinet
Table 4. Minimum Clearances
7. RETURN AIR PROVISIONS
U.S.A. home manufacturers shall comply with all of the
following conditions to have acceptable return air systems for
closet installed forced air heating appliances:
a. Regardless of the location, the return air opening into
the closet shall not be less than specified in the
appliance’s listing.
b. Means shall be provided to prevent inadvertent closure
by a flat object placed over the return air opening
when it is located in the floor of the closet (versus the
vertical front or side wall).
c. The cross-sectional area of the return duct system
leading into the closet, when located in the floor or
ceiling shall not be less than 235 square inches (or
390 square inches for 5 ton ready M1 Furnaces).
d. The total free area of openings in the floor or ceiling
registers serving the return air duct system must be
at least 352 sq. in. At least one register should be
located where it is not likely to be covered by carpeting,
boxes and other objects.
e. Materials located in the return duct system must have
a flame spread classification of 200 or less. This
includes a closet door if the furnace is in a closet.
f.
Noncombustible pans having 1" upturned flanges are
located beneath openings in a floor duct system.
g. Wiring materials located in the return duct system
shall conform to Articles 300-22 of the National
Electrical Code (ANSI C1/NFPA-70).
h. Gas piping is not run in or through the return duct
system.
i.
Test the negative pressure in the closet with the air-
circulating fan operating at high speed and the closet
closed. The negative pressure is to be no more
negative than minus 0.05 inch water column.
CAUTION:
HAZARD OF ASPHYXIATION: Negative
pressure inside the closet, with closet door
closed and the furnace blower operating on
high speed, shall be no more negative than
minus 0.05 inch water column.
!
ALL MODELS
CLOSET
ALCOVE
Front
6"
18"
Back
0"
0"
Sides
0"
0"
Roof Jack
0"
0"
Top
6"
6"
Top and Sides of Duct
0"
0"
Bottom of Duct
B Cabinet
0"
0"
A Cabinet (w/ coil box)
0"
0"
A Cabinet (w/o coil box)
1/4"
1/4"
