Installation In Horizontal Applications; Air Ducts; General - Payne PG9MAB Series A Installation Manual

1. Determine application being installed from Table 3.
2. Construct hole in floor per dimensions specified in Table 3 and Fig. 21.
3. Construct plenum to dimensions specified in Table 3 and Fig. 21.
4. If downflow subbase (KGASB) is used, install as shown in Fig. 22.
If coil assembly CD5, CK5 or Coil Box KCAKC is used, install as shown in Fig. 23.
NOTE: Remove furnace perforated, discharge duct flanges when they interfere with mating flanges on coil on downflow subbase. To remove
furnace perforated, discharge duct flange, use wide duct pliers or duct flange tool to bend flange back and forth until it breaks off. Be careful of
sharp edges. (See Fig. 24.)
CAUTION: UNIT MAY NOT OPERATE
Failure to follow this caution may result in intermittent unit operation.
Do not bend duct flanges inward as shown in Fig. 24. This will affect airflow across heat exchangers and may cause limit cycling or
premature heat exchanger failure. Remove duct flange completely or bend it inward a minimum of 210° as shown in Fig. 24.
NOTE: For 140 size unit when installed in downflow orientation, cut the white jumper wire off between terminals PL1-7 and PL1-9. Do not cut
white jumper between terminals PL1-7 and PLI-11. Refer to Fig. 35 for location of jumper. Cut jumper close to connector and remove wire to
avoid a short circuit.
PROCEDURE 3—INSTALLATION IN HORIZONTAL APPLICATIONS
CAUTION: UNIT MAY NOT OPERATE
Failure to follow this caution may result in intermittent unit operation.
The entire length of furnace MUST be supported when furnace is used in a horizontal position to ensure proper draining. When
suspended, bottom brace supports sides and center blower shelf. When unit is supported from the ground, blocks or pad should
support sides and center blower shelf area.
These furnaces can be installed horizontally in either horizontal left or right discharge position. In a crawlspace, furnace can either be hung from
floor joist or installed on suitable blocks or pad. Furnace can be suspended from each corner by hanger bolts and angle iron supports. (See Fig.
25 or 26.) Cut hanger bolts (4 each 3/8-in. all-thread rod) to desired length. Use 1 X 3/8-in. flat washers, 3/8-in. lockwashers, and 3/8-in. nuts on
hanger rods as shown in Fig. 25 or 26. Dimples are provided for hole locations. (See Fig. 2.)
NOTE: The 140 Size unit may not be installed in non-direct vent applications.
PROCEDURE 4—AIR DUCTS
A. 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 static pressure.
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 a duct(s) sealed to the furnace casing and terminating outside the space containing the furnace.
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Fig. 20—Leveling Legs
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