Operating instructions
WARNING: Never purge a gas line into a combustion
chamber. Never test for gas leaks with an open flame. Use
a commercially available soap solution made specifically
for the detection of leaks to check all connections. A
failure to follow this warning could result in fire, explo-
sion, personal injury, or death.
WARNING: Use proper length of pipe to avoid stress
on gas control manifold. Failure to follow this warning
could result in a gas leak resulting in fire, explosion,
personal injury, or death.
Install a sediment trap in riser leading to furnace. Trap can be
installed by connecting a tee to riser leading to furnace so
straight-through section of tee is vertical. Then connect a capped
nipple into lower end of tee. Capped nipple should extend below
level of gas controls. Place a ground joint union between gas
control manifold and manual gas shutoff valve. (See Fig. 26.)
CAUTION: If a flexible connector is required or al-
lowed by authority having jurisdiction, black iron pipe
shall be installed at furnace gas control valve and extend
a minimum of 2 in. outside furnace casing. Failure to
follow this caution will result in potential chaffing of
flexible gas connection.
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 appliance.
WARNING: FIRE OR EXPLOSION HAZARD
Failure to follow the safety warnings exactly could result
in serious injury, death or property damage.
Never test for gas leaks with an open flame. Use a
commercially available soap solution made specifically
for the detection of leaks to check all connections. A fire
or explosion may result causing property damage, per-
sonal injury or loss of life.
An accessible manual shutoff valve MUST be installed external of
furnace casing and within 6 ft of furnace. A 1/8-in. NPT plugged
tapping, accessible for test gauge connection, MUST be installed
immediately upstream of gas supply connection to furnace and
downstream of manual shutoff valve.
NOTE: The gas 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. wc) stated on gas valve. (See
Fig. 57.)
Piping should be pressure and leak tested in accordance with
NFGC in the United States or NSCNGPIC in Canada, local, and
national plumbing and gas codes before the furnace has been
connected. After all connections have been made, purge lines and
check for leakage at furnace prior to operating furnace.
If pressure exceeds 0.5 psig (14-in. wc), gas supply pipe must be
disconnected from furnace and capped before pressure test. If test
pressure is equal to or less than 0.5 psig (14-in. wc), turn off
electric shutoff switch located on furnace gas control valve and
accessible manual shutoff valve before test. It is recommended that
ground joint union be loosened before pressure testing. After all
connections have been made, purge lines and check for leakage.
The gas supply pressure shall be within the maximum and
minimum inlet supply pressures marked on the rating plate with
the furnace burners ON and OFF.
VIII. ELECTRICAL CONNECTIONS
See Fig. 27 for field wiring diagram showing typical field 115-v
and 24-v wiring. Check all factory and field electrical connections
for tightness.
Field-supplied wiring shall conform with the limitations of 63°F
(35°C) rise.
WARNING: Blower access panel door switch opens
115-v power to control center. No component operation
can occur. Do not bypass or close switch with panel
removed. Failure to follow this warning could result in
personal injury or death.
CAUTION: Furnace control must be grounded for
proper operation or control will lock out. Control is
grounded through green/yellow wire routed to gas valve
and burner box screw. Failure to follow this caution will
result in intermittent unit operation.
A. 115–v Wiring
Before proceeding with electrical connections, make certain that
voltage, frequency, and phase correspond to that specified on
furnace rating plate. Also, check to be sure that service provided
by power supply is sufficient to handle load imposed by this
equipment. Refer to rating plate or Table 4 for equipment electrical
specifications. Make all electrical connections in accordance with
National Electrical Code (NEC) ANSI/NFPA 70-2002 and any
local codes or ordinances that might apply. For Canadian instal-
lations, all electrical connections must be made in accordance with
TABLE 3—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
1 1.049 680 465 375 320 285
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 9.2 NFGC.
Fig. 26—Typical Gas Pipe Arrangement
A93324
UNION
SEDIMENT
TRAP
MANUAL
SHUTOFF
VALVE
(REQUIRED)
GAS
SUPPLY
—19—
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