Ductwork Acoustical Treatment; Supply Air Connections; Return Air Connections - Payne PG9MAB Series A Installation Manual

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.
Flexible connections should be used between ductwork and furnace to prevent transmission of vibration. Ductwork passing through unconditioned
space should be insulated to enhance system performance. When air conditioning is used, a vapor barrier is recommended.
Maintain a 1-in. clearance from combustible materials to supply air ductwork for a distance of 36 in. horizontally from the furnace. See NFPA
90B or local code for further requirements.
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 air stream. The cover attachment shall prevent leaks.
B. Ductwork Acoustical Treatment
Metal duct systems that do not have a 90 degree elbow and 10 ft 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.
C. Supply Air Connections
UPFLOW FURNACES
Connect supply-air duct to 3/4-in. flange on furnace supply-air outlet. The supply-air duct attachment must ONLY be connected to furnace
supply-/outlet-air duct flanges or air conditioning coil casing (when used). DO NOT cut main furnace casing to attach supply side air duct,
humidifier, or other accessories. All accessories MUST be connected external to furnace main casing.
DOWNFLOW FURNACES
Connect supply-air duct to supply-air opening on furnace. The supply-air duct attachment must ONLY be connected to furnace supply/outlet or
air conditioning coil casing (when used), when installed on non-combustible material. When installed on combustible material, supply-air duct
attachment must ONLY be connected to an accessory subbase or factory approved air conditioning coil casing. DO NOT cut main furnace casing
to attach supply side air duct, humidifier, or other accessories. All accessories MUST be connected external to furnace main casing.
HORIZONTAL FURNACES
Connect supply-air duct to supply air opening on furnace. The supply-air duct attachment must ONLY be connected to furnace supply/outlet or
air conditioning coil casing (when used). DO NOT cut main furnace casing to attach supply side air duct, humidifier, or other accessories. All
accessories MUST be connected external to furnace main casing.
D. Return Air Connections
The furnace and its return air system shall be designed and installed so that negative pressure created by the air circulating fan cannot affect another
appliance's combustion air supply or act to mix products of combustion with circulating air, and that the air circulating fan of the furnace, if
installed in an enclosure communicating with another fuel-burning appliance not of the direct-vent type, shall be operable only when any door or
panel covering an opening in the furnace fan compartment or in a return air plenum on ducts is in the closed position.
WARNING: FIRE HAZARD
A failure to follow this warning could result in fire, personal injury, or death.
Never connect return-air ducts to the back of the furnace. Return-air duct connections on furnace side(s) permitted in upflow
applications only.
UPFLOW FURNACES
The return-air duct must be connected to bottom, sides (left or right), or a combination of bottom and side(s) of main furnace casing as shown
in Fig. 2. Bypass humidifier may be attached into unused side return air portion of the furnace casing. DO NOT connect any portion of return-air
duct to back of furnace casing.
PERFORATED
DISCHARGE DUCT
FLANGE
210°
MIN
Fig. 24—Duct Flanges
—25—
NO
YES
YES
A93029