Supply Air Connections; Acoustical Treatments; Furnace Installation; General Requirements - Nordyne M4RC Upflow Installation Instructions Manual

• Noncombustible pans having 1" upturned fl anges are
located beneath openings in a fl oor duct system.
• Wiring materials located in the return duct system shall
conform to Articles 300-22 of the National Electrical
Code (ANSI C1/NFPA-70).
• Gas piping is not run in or through the return duct
system.
• 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.
• Air conditioning systems may require more duct, register
and open louver area to obtain necessary airfl ow. Use
NORDYNE's certiduct program to determine proper
duct size for A/C.
• For floor return systems, the manufactured home
manufacturer shall affi x a prominent marking on or
near the appliance where it can be easily read when
the closet door is open. The marking shall read:
CAUTION:
HAZARD OF ASPHYXIATION: Do not cover
or restrict return air opening.

Supply Air Connections

For proper air distribution, the supply duct system must be
designed so that the static pressure measured external
to the furnace does not exceed the listed static pressure
rating shown on the furnace rating plate. The supply
air must be delivered to the heated space by duct(s)
secured to the furnace casing, running full size and
without interruption.
Three typical distribution systems are shown in Figure 10.
The location, size, and number of registers should be
selected on the basis of best air distribution and fl oor
plan of the home.
A Single trunk duct
Dual trunk duct
B
w/crossover connector
Transition duct
w/branches
C
Figure 10. Typical Supply Duct System

Acoustical Treatments

Damping ducts, fl exible vibration isolators, or pleated
media-style fi lters on the return air inlet of the furnace
may be used to reduce the transmission of equipment
noise eminating from the furnace. These treatments can
produce a quieter installation, particularly in the heated
space. However, they can increase the pressure drop in
the duct system. Care must be taken to maintain the proper
maximum pressure rise across the furnace, temperature
rise and fl ow rate. This may mean increasing the duct size
and/or reducing the blower speed. These treatments must
be constructed and installed in accordance with NFPA and
SMACNA construction standards. Consult with local codes
for special requirements. For best sound performance,
install all the needed gaskets and grommets around
penetrations into the furnace, such as for electrical wiring.

FURNACE INSTALLATION

*RC series gas furnaces are shipped ready for installation
in the upfl ow position with upfl ow return air. *RL series
gas furnaces may only be used for downfl ow operation.
See Table 1 (page 9) for the required clearances needed
to move the furnace to its installation point (hallways,
doorways, stairs, etc).

General Requirements

• The furnace must be leveled at installation and attached
to a properly installed duct system. Do not use the
back of the furnace for return air. See page 14 for
circulating requirements.
• The furnace must be installed so that all electrical
components are protected from water.
• The dimensions of the room or alcove must be able to
accommodate the overall size of the furnace and the
installation clearances listed in Table 1.
• The furnace must be installed upstream from a
refrigeration system.
• The plenum attached to the A/C coil box and ductwork
within 3 ft. of the furnace must be installed so that
surfaces are at least 1/4" from combustible construction.
• The cabinet plug must always be used to close the hole
in the side of the furnace when rotating the inducer.
• Upfl ow and downfl ow models must be installed with
the Nordyne A/C coil box which are listed according to
the cabinet size of the furnace: "B" cabinet - 920169,
"C" cabinet - 920171, and "D" cabinet - 920172.

Requirements and Codes

The installer must be familiar with and comply with all
local codes and regulations applicable to the installation of
heating appliances and related equipment. In the absence
of local codes, the installation must conform with these
instructions and the current provisions of one or more of
the following standards:
• Federal Manufactured Home Constructions & Safety
Standard (H.U.D. Title 24, Part 3280.707[a][2])
• The Standard for Manufactured Home Installations
(Manufactured Home Sites, Communities, and Set-
Ups) ANSI A225.1 and/or CAN/CSA-2240 MH Series).
• American National Standard (ANSI-119.2/NFPA-501C)
for all recreational vehicle installations.
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