4. Adjust outside nut to provide desired height, and tighten
inside nut to secure arrangement.
V. GAS PIPING
Gas piping must be installed in accordance with national and local
codes. Refer to the current edition of the NFGC. Canadian
installations must be installed in accordance with NSCNGPIC and
all authorities having jurisdiction.
Refer to Table 4 for the recommended gas pipe size. Risers must
be used to connect to the furnace and the meter.
CAUTION: If a flexible connector is required or al-
lowed by the authority having jurisdiction, black iron
pipe shall be installed at the gas valve and extend a
minimum of 2 in. outside the furnace casing.
Piping should be pressure tested in accordance with local and
national plumbing and gas codes before the furnace has been
attached. If the pressure exceeds 0.5 psig (14-in. wc), the gas
supply pipe must be disconnected from the furnace and capped
before the pressure test. If the test pressure is equal to or less than
0.5 psig (14-in. wc), turn off electric shutoff switch located on the
gas valve before the test. It is recommended that the ground joint
union be loosened before pressure testing. After all connections
have been made, purge the lines and check for leakage with
regulated gas supply pressure.
Install a sediment trap in the riser leading to the furnace. The trap
can be installed by connecting a tee to the riser leading from the
furnace. Connect a capped nipple into the lower end of the tee. The
capped nipple should extend below the level of the gas controls.
(See Fig. 7.)
Apply joint compound (pipe dope) sparingly and only to the male
threads of each joint. The compound must be resistant to the action
of propane gas.
An accessible manual shutoff valve MUST be installed upstream
of the furnace gas controls and within 72 in. of the furnace. A
1/8-in. NPT plugged tapping, accessible for test gage connection,
MUST be installed immediately upstream of the gas supply
connection to the furnace and downstream of the manual shutoff
valve. Place ground joint union between the gas control manifold
and the manual shutoff valve.
Fig. 5—Bottom Filter Arrangement
(Control Removed for Clarity)
A96030
WASHABLE
FILTER
FILTER
SUPPORT
FILTER
RETAINER
241⁄2-IN. WIDE 
CASINGS ONLY:
CUT AND FOLD
FACTORY-PROVIDED
FILTERS AS SHOWN
TO DESIRED SIZE.
171⁄2-IN. WIDE 
CASINGS ONLY:
INSTALL FIELD-SUPPLIED
FILTER FILLER STRIP
UNDER FILTER.
1″
24 1/2″
3″
TABLE 3—FILTER INFORMATION (IN.)
FURNACE
CASING WIDTH FILTER SIZE* FILTER TYPE
Side Return Bottom Return
14-3/16 (1) 16 X 25 X 1† (1)14 X 25 X 1 Cleanable
17-1/2 (1) 16 X 25 X 1† (1)16 X 25 X 1 Cleanable
21 (1) 16 X 25 X 1 (1)20 X 25 X 1† Cleanable
24-1/2 (2) 16 X 25 X 1† (1)24 X 25 X 1 Cleanable
*Filters can be field modified by cutting the frame as marked and folding to the
desired size. Alternate sizes can be ordered from your distributor or dealer.
† Factory-provided with the furnace.
Fig. 6—Leveling Leg Installation A89014
1 3⁄4″
1 3⁄4″
1 3⁄4″
1 3⁄4″
5⁄16″
5⁄16″
5⁄16″
5⁄16″
TABLE 4—MAXIMUM CAPACITY OF PIPE*
NOMINAL IRON
PIPE SIZE
(IN.)
INTERNAL
DIAMETER
(IN.)
LENGTH OF PIPE (FT)
10 20 30 40 50
1/2 0.622 175 120 97 82 73
3/4 0.824 360 250 200 170 151
11.049 680 465 375 320 285
1-1/4 1.380 1400 950 770 660 580
1-1/2 1.610 2100 1460 1180 990 900
* Cubic ft of gas per hr for gas pressures of 0.5 psig (14-in. wc) or less, and a
pressure drop of 0.5-in. wc (based on a 0.60 specific gravity gas). Ref: Table
10-2 NFPA 54-1992.
—6—
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