INSTALLATION INSTRUCTIONS
Gas Furnace: N9MSE
440 01 4103 03
29
Specifications subject to change without notice.
!
WARNING
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Gas valve inlet and/or inlet pipe must remain capped
until gas supply line is permanently installed to protect
the valve from moisture and debris. Also, install a sedi-
ment trap in the gas supply piping at the inlet to the
gas valve.
Gas piping must be installed in accordance with national and
local codes. Refer to current edition of NFGC in the U.S.A.
Refer to current edition of CAN/CSA B149.1 in Canada.
Installations must be made in accordance with all authorities
having jurisdiction. If possible, the gas supply line should be a
separate line running directly from meter to furnace.
NOTE
: Use a back
−
up wrench on the inlet of the gas valve
when connecting the gas line to the gas valve.
NOTICE
In the state of Massachusetts:
1. Gas supply connections MUST be performed by a li-
censed plumber or gas fitter.
2. When flexible connectors are used, the maximum
length shall not exceed 36
−
in. (915 mm).
3. When lever handle type manual equipment shutoff
valves are used, they shall be T
−
handle valves.
4. The use of copper tubing for gas piping is NOT ap-
proved by the state of Massachusetts.
Refer to
Table 10
for recommended gas pipe sizing. Risers
must be used to connect to furnace and to meter. Support all
gas piping with appropriate straps, hangers, etc. Use a
minimum of one hanger every 6 ft. (1.8 M). Joint compound
(pipe dope) should be applied sparingly and only to male
threads of joints. Pipe dope must be resistant to the action of
propane gas.
!
WARNING
FIRE OR EXPLOSION HAZARD
A failure to follow this warning could result in personal in-
jury, death, and/or property damage.
If local codes allow the use of a flexible gas appliance
connector, always use a new listed connector. Do not use
a connector which has previously served another gas ap-
pliance. Black iron pipe shall be installed at the furnace
gas control valve and extend a minimum of 2
−
in. (51 mm)
outside the furnace.
!
CAUTION
FURNACE DAMAGE HAZARD
Failure to follow this caution may result in furnace dam-
age.
Connect gas pipe to furnace using a backup wrench to
avoid damaging gas controls and burner misalignment.
Table 10 Maximum Capacity of Pipe
NOMINAL
IRON PIPE
SIZE
IN. (MM)
INTERNAL
DIA.
IN. (MM)
LENGTH OF PIPE
−
FT (M)
10
(3.0)
20
(6.0)
30
(9.1)
40
(12.1)
50
(15.2)
1/2 (13)
0.622 (158)
175
120
97
82
73
3/4 (19)
0.824 (20.9)
360
250
200
170
151
1 (
25)
1.049 (26.6)
680
465
375
320
285
1‐1/4 (32)
1.380 (35.0)
1400
950
770
660
580
1‐1/2 (39)
1.610 (40.9)
2100
1460
1180
990
900
* Cubic ft of gas per hr for gas pressures of 0.5 psig (14-in. w.c.) or less and
a pressure drop of 0.5-in. w.c. (based on a 0.60 specific gravity gas). Ref:
Table 10
above,
and 6.2 of NFPA54/ANSI Z223.1-2012.
An accessible manual equipment shutoff valve MUST be
installed external to furnace casing and within 6 ft. (1.8 M) of
furnace.
Install a sediment trap in riser leading to furnace as shown in
Figure 32
. Connect a capped nipple into lower end of tee.
Capped nipple should extend below level of furnace gas
controls. Place a ground joint union between furnace gas
control valve and exterior manual equipment gas shutoff valve.
Figure 32
Typical Gas Pipe Arrangement
L10F030
A 1/8
−
in. (3 mm) NPT plugged tapping, accessible for test
gauge connection, MUST be installed immediately upstream of
gas supply connection to furnace and downstream of manual
equipment shutoff valve.
Piping should be pressure and leak tested in accordance with
the current addition of the NFGC in the United States, local,
and national plumbing and gas codes before the furnace has
been connected. Refer to current edition of NSCNGPIC in
Canada. After all connections have been made, purge lines
and check for leakage at furnace prior to operating furnace.
NOTE:
The furnace gas control valve inlet pressure tap
connection is suitable to use as test gauge connection
providing test pressure DOES NOT exceed maximum 0.5 psig
(14
−
in. w.c.) stated on gas control valve. (See
Figure 33
)
