used on the condensate drip leg and line. Heating
cable kit is available from Lennox in various lengths;
6feet (1.8m) - kit no. 18K48; 24 feet (7.3m) - kit no.
18K49; and 50 feet (15.2m) - kit no. 18K50.
..... I
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 bottom of the valve as shown in
figure 23.
LEFT SIDE PIPING
MANUAL
MAIN SHUT-
OFF
VALVE
1/8 IN. NPT
PLUGGED
TAP _ I_, _
GAS VALVE
_ .... _ RIGHT SIDE PIPING
___ _=_L_ (STANDARD)
_' _=" 1/8 IN. NPT
/ B PLUGGED
/ /TAP
GAS VALVE
FIGURE 23
2- When connecting the gas supply, factors such as
length of run, number of fittings and furnace rating
must be considered to avoidexcessive pressure drop
Table 5 lists recommended pipe sizes for typical ap-
plications.
NOTE- Use two wrenches when connecting gas pip-
ing to avoid transferring torque to the manifold.
3 - The gas piping must not run in or through air ducts,
clothes chutes, gas vents or chimneys, dumb waiters
or elevator shafts. Center gas line through pipinghole.
Gas line should not touch side of unit.
4-
5-
When left-hand gas plumbing is required, gas line
should be installedin the lower half of knockoutso that
piping willclear combustion air inducer.See figure 23.
The pipingshould be sloped 1/4 inch (6.4 ram) per 15
feet (4.57 m) upward toward the meter from the fur-
nace. The piping must be supported at proper inter-
vals [every 8 to 10 feet (2.44 to 3.01 m)] using suitable
hangers or straps.A drip leg should be installedinver-
tical pipe runs to the unit.
In some localities, codes may require installation of a
manual main shut-offvalveand union(furnished by in-
staller) external to the unit. Union must be of the
ground joint type.
AIMPORTANT
HO"A' ES'P"E"O"EII
118IN.13.2mmlN.P.T.1_. II ISOLATE
/|
FIGURE 24
NO TE - Install a 1/8 inch NPT plugged tap in the field pip-
ing upstream of the gas supply connection to the unit.
The tap must be accessible for test gauge connection.
See figure 24.
Leak Check
After gas piping has been completed, carefully check all
piping connections (factory and field) for gas leaks. Use a
leak detecting solution or other preferred means.
ACAUTION
Page 15
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