Gas Piping - Lennox ELITE Series Installation Instructions Manual

Gas Piping

Gas supply piping should not allow more than 0.5"W.C.
drop in pressure between gas meter and unit. Supply gas
pipe must not be smaller than unit gas connection.
CAUTION
If a flexible gas connector is required or allowed by the
authority that has jurisdiction, black iron pipe shall be
installed at the gas valve and extend outside the furnace
cabinet. The flexible connector can then be added
between the black iron pipe and the gas supply line.
WARNING
Do not over torque (800 in-lbs) or under torque (350 in-
lbs) when attaching the gas piping to the gas valve.
1 - Gas piping may be routed into the unit through either
the left- or right-hand side. Supply piping enters into
the gas valve from the side of the valve as shown
in FIGURE 56. Connect the gas supply piping into
the gasvalve. The maximum torque is 800 in lbs and
minimum torque is 350 in lbs when when attaching
the gas piping to the gas valve.
2 - When connecting gas supply, factors such as length
of run, number of fittings and furnace rating must
be considered to avoid excessive pressure drop.
Table 9 lists recommended pipe sizes for typical
applications.
NOTE - Use two wrenches when connecting gas
piping to avoid transferring torque to the manifold.
3 - Gas piping must not run in or through air ducts,
clothes chutes, chimneys or gas vents, dumb waiters
or elevator shafts. Center gas line through piping
hole. Gas line should not touch side of unit. See
FIGURE 56 and FIGURE 57.
4 - Piping should be sloped 1/4 inch per 15 feet (6mm
per 5.6m) upward toward the gas meter from the
furnace. The piping must be supported at proper
intervals, every 8 to 10 feet (2.44 to 3.05m), using
suitable hangers or straps. Install a drip leg in
vertical pipe runs to serve as a trap for sediment or
condensate.
5 - A 1/8" N.P.T. plugged tap or pressure post is located
on the gas valve
6 - In some localities, codes may require installation of a
manual main shut-off valve and union (furnished by
installer) external to the unit. Union must be of the
ground joint type.
Compounds used on threaded joints of gas piping must
be resistant to the actions of liquified petroleum gases.
Leak Check
After gas piping is completed, carefully check all piping
connections (factory- and field-installed) for gas leaks.
Use a leak detecting solution or other preferred means.
Never use an open flame to test for gas leaks. Check all
connections using a commercially available soap solution
made specifically for leak detection.
The furnace must be isolated from the gas supply system
by closing its individual manual shut-off valve during any
pressure testing of the gas supply system at pressures
greater than or equal to 1/2 psig (3.48 kPa, 14 inches w.c.).
MANUAL MAIN SHUT-OFF
VALVE WILL NOT HOLD
NORMAL TEST PRESSURE
1/8" N.P.T. PLUGGED TAP
When testing pressure of gas lines, gas valve must be
disconnected and isolated. See FIGURE 55. Gas valves
can be damaged if subjected to pressures greater than
1/2 psig (3.48 kPa).
FIRE OR EXPLOSION HAZARD
Failure to follow the safety warnings exactly could result
in serious injury, death, or property damage. Never use
an open flame to test for gas leaks. Check all connections
using a commercially available soap solution made
specifically for leak detection. Some soaps used for leak
detection are corrosive to certain metals. Carefully rinse
piping thoroughly after leak test has been completed.
Page 35
IMPORTANT
CAP
FURNACE
ISOLATE
GAS VALVE
FIGURE 55
IMPORTANT
WARNING