Lennox ML193UHE Series Unit Information page 23

NOTE - Assembly should be completed within 20
seconds after last application of cement. Hammer
blows should not be used when inserting pipe.
8 - After assembly, wipe excess cement from pipe at
end of fitting socket. A properly made joint will show
a bead around its entire perimeter. Any gaps may
indicate an improper assembly due to insufficient
solvent.
9 - Handle joints carefully until completely set.
Venting Practices
Piping Suspension Guidelines
SCHEDULE 40
PVC - 5'
all other pipe* - 3'
* See Piping and Fittings Specifications table
NOTE - Isolate piping at the point where it exits the outside wall or
roof in order to prevent transmission of vibration to the structure.
Wall Thickness Guidelines
24" maximum
3/4" minimum
n i s d i e
FIGURE 21
1 - In areas where piping penetrates joists or interior
walls, hole must be large enough to allow clearance
on all sides of pipe through center of hole using a
hanger.
2 - When furnace is installed in a residence where unit
is shut down for an extended period of time, such
as a vacation home, make provisions for draining
condensate collection trap and lines.
Exhaust Piping (FIGURE 23, FIGURE 25 & FIGURE 26)
Route piping to outside of structure. Continue with instal-
lation following instructions given in piping termination
section.
Wall
o u s t d i e
Page 23
REPLACING FURNACE THAT WAS PART OF A
COMMON VENT SYSTEM
CHIMNEY
OR GAS
VENT
(Check sizing
for water
heater only)
FURNACE
(Replaced)
If replacing a furnace which was
commonly vented with another gas appliance, the size
of the existing vent pipe for that gas appliance must be
checked. Without the heat of the original furnace flue
products, the existing vent pipe is probably oversized for
the single water heater or other appliance. The vent
should be checked for proper draw with the remaining
appliance.
FIGURE 22
CAUTION
Do not discharge exhaust into an existing stack
or stack that also serves another gas appliance. If
vertical discharge through an existing unused stack
is required, insert PVC pipe inside the stack until the
end is even with the top or outlet end of the metal
stack.
CAUTION
The exhaust vent pipe operates under positive
pressure and must be completely sealed to prevent
leakage of combustion products into the living
space.
Vent Piping Guidelines
NOTE - Lennox has approved the use of DuraVent
Centrotherm manufactured vent pipe and terminations
as an option to PVC. When using the PolyPro
raVent or InnoFlue by Centrotherm venting system the
®
vent pipe requirements stated in the unit installation in-
struction – minimum & maximum vent lengths, termination
clearances, etc. – apply and must be followed. Follow the
instructions provided with PoyPro by DuraVent and Inno-
Flue by Centrotherm venting system for assembly or if re-
quirements are more restrictive. The PolyPro by Duravent
and InnoFlue by Centrotherm venting system must also
follow the uninsulated and unconditioned space criteria
listed in TABLE 15.
WATER
HEATER
OPENINGS
(To Adjacent
Room)
and
®
by Du-
®