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N80MSN/N80MSL: Installation, Start–Up, Operating and Service and Maintenance Instructions
Fig. 15 – Horizontal Unit Suspension
Roll-Out Protection
Provide a minimum 17-3/4 in. x 22 in. (451 mm x 559 mm) piece of
sheet metal for flame roll-out protection in front of burner area for
furnaces closer than 12 inches (305 mm) above the combustible deck or
suspended furnaces closer than 12 inches (305 mm) to joists. The sheet
metal MUST extend underneath the furnace casing by 1 in. (25 mm)
with the door removed.
The bottom closure panel on furnaces of widths 17-1/2 in. (445 mm) and
larger may be used for flame roll-out protection when bottom of furnace
is used for return air connection. See
roll-out shield.
Fig. 16 – Horizontal Suspension with Straps
Bottom Return Air Inlet
These furnaces are shipped with bottom closure panel installed in bottom
return-air opening. Remove and discard this panel when bottom return
air is used. To remove bottom closure panel, perform the following:
1. Tilt or raise furnace and remove two screws holding bottom filler
panel (see
Fig.
9).
2. Rotate bottom filler panel downward to release holding tabs.
3. Remove bottom closure panel.
4. Reinstall bottom filler panel and screws. Side Return Air Inlet
Side Return Air Inlet
These furnaces are shipped with bottom closure panel installed in bottom
return-air opening. This panel MUST be in place when side return air
inlet(s) is used without a bottom return air inlet.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
A10130
Fig. 14
for proper orientation of
A10131
Not all horizontal furnaces are approved for side return air connections
(see
Fig.
20).
FILTER ARRANGEMENT
!
CARBON MONOXIDE AND POISONING
HAZARD
Failure to follow this warning could result in personal injury, or death.
Never operate a furnace without a filter or with filter access door
removed.
There are no provisions for an internal filter rack in these furnaces.
A field-supplied accessory external filter is required.
Refer to the instructions supplied with the external filter rack for
assembly and installation options.
AIR DUCTS
General Requirements
The duct system should be designed and sized according to accepted
national standards such as those published by: Air Conditioning
Contractors Association (ACCA), Sheet Metal and Air Conditioning
Contractors National Association (SMACNA) or American Society of
Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) or
consult The Air Systems Design Guidelines reference tables available
from your local distributor. The duct system should be sized to handle
the required system design CFM at the design external static pressure.
The furnace airflow rates are provided in
(with filter).
When a furnace is installed so that the supply ducts carry air circulated
by the furnace to areas outside the space containing the furnace, the
return air shall also be handled by duct(s) sealed to the furnace casing
and terminating outside the space containing the furnace.
Secure ductwork with proper fasteners for type of ductwork used. Seal
supply- and return-duct connections to furnace with code approved tape
or duct sealer.
NOTE: Flexible connections should be used between ductwork and
furnace to prevent transmission of vibration. Ductwork passing through
unconditioned space should be insulated and sealed to enhance system
performance. When air conditioning is used, a vapor barrier is
recommended.
Maintain a 1-in. (25 mm) clearance from combustible materials to
supply air ductwork for a distance of 36 in. (914 mm) horizontally from
the furnace. See NFPA 90B or local code for further requirements.
Ductwork Acoustical Treatment
NOTE: Metal duct systems that do not have a 90 degree elbow and 10
ft. (3 M) of main duct to the first branch take-off may require internal
acoustical lining. As an alternative, fibrous ductwork may be used if
constructed and installed in accordance with the latest edition of
SMACNA construction standard on fibrous glass ducts. Both acoustical
lining and fibrous ductwork shall comply with NFPA 90B as tested by
UL Standard 181 for Class 1 Rigid air ducts.
Supply Air Connections
For a furnace not equipped with a cooling coil, the outlet duct shall be
provided with a removable access panel. This opening shall be
accessible when the furnace is installed and shall be of such a size that
the heat exchanger can be viewed for possible openings using light
assistance or a probe can be inserted for sampling the airstream. The
cover attachment shall prevent leaks.
12
WARNING
Table
9-AIR DELIVERY-CFM
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