Gas Piping; Leak Check; Upflow Application Right Side Piping; Left Side Piping - Lennox G71MPP-36B-070 Installation Instructions Manual

-&CAUTION
AWARNING
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
figures 36 and 37.
2 - When connecting gas supply, factors such as length of
run, number of fittings and furnace rating must be con-
sidered to avoid excessive pressure drop. Table 9 lists
recommended pipe sizes for typical applications.
NOTE - Use two wrenches when connecting gas pip-
ing 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 eleva-
tor shafts. Center gas line through piping hole. Gas
line should not touch side of unit. See figures 36 and
37.
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, ev-
ery 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 to facilitate test gauge connection.
See figures 44.
6 - In some localities, codes may require installation of a
manual main shut-off valve and union (furnished by in-
staller) external to the unit. Union must be of the
ground joint type.
,IMPORTANT
MANUAL MAIN SHUT-OFF
VALVE WILL NOT HOLD
NORMAL TEST PRESSURE "_
I
CAP .------...._t-t
FURNACE
ISOLATE
GAS VALVE
FIGURE 35
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.
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 less
than or equal to 1/2 psig (3.48 kPa, 14 inches w.c.).
AIMPORTANT
AWARNING
Upflow Application AUTOMATIC
Left Side Piping GAS VALVE
(Standard)
(with manual
shut-off valve)
MANUAL
MAIN SHUT-OFF
VALVE
GROUND
JOINT
UNION
J
!
Upflow Application
Right Side Piping
(Alternate)
MANUAL
MAIN SHUT-OFF
VALVE
JOINT
UNION
DRIP LEG
DRIP LEG
FIELD
PROVIDED
AND INSTALLED
Figure 36
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