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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
Exhaust Piping (FIGURE 23, FIGURE 26 and FIGURE
27)
The vent adapter must be attached to the exhaust cou-
pling on the furnace top panel. Use provided bands. See
steps below.
1 - Remove the caution tag from vent adapter.
2 - Fully insert vent adapter with both bands loosely
attached on the furnace exhaust coupling
3 - Insert PVC exhaust pipe through vent adapter. Ensure
vent pipe is fully seated into exhaust coupling.
4 - Tighten both top and bottom bands to 40in-lbs.
NOTE - PVC / ABS / NORYL transition solvent cement
WELD-ON 4052 (or equivalent) must be used for con-
necting PVC exhaust pipe to NORYL furnace exhaust
coupling.
Route piping to outside of structure. Continue with instal-
lation following instructions given in piping termination
section.
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.
WATER
HEATER
OPENINGS
(To Adjacent
Room)
Page 17
Flue Coupling To Exhaust Coupling
PVC
Exhaust Pipe
Top Band
(torque to 40in-lbs)
Bottom Band
(torque to 40in-lbs)
FIGURE 23
Vent Piping Guidelines
NOTE - Lennox has approved the use of DuraVent® and
Centrotherm manufactured vent pipe and terminations as
an option to PVC. When using the PolyPro® by DuraVent
or InnoFlue® by Centrotherm venting system the vent
pipe requirements stated in the unit installation instruc-
tion – 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 7.
The EL195UHNE can be installed as either a Non-Di-
rect Vent or a Direct Vent gas central furnace.
NOTE - In Non-Direct Vent installations, combustion air
is taken from indoors and flue gases are discharged out-
doors. In Direct Vent installations, combustion air is taken
from outdoors and flue gases are discharged outdoors.
Intake and exhaust pipe sizing -- Size pipe accord-
ing to TABLE 4 and TABLE 5. Count all elbows inside
and outside the home. TABLE 4 lists the minimum vent
pipe lengths permitted. TABLE 5 lists the maximum pipe
lengths permitted. Regardless of the diameter of pipe
used, the standard roof and wall terminations described
in section Exhaust Piping Terminations should be used.
Exhaust vent termination pipe is sized to optimize the ve-
locity of the exhaust gas as it exits the termination. Refer
to TABLE 8.
In some applications which permit the use of several dif-
ferent sizes of vent pipe, a combination vent pipe may be
used. Contact Lennox' Application Department for assis-
tance in sizing vent pipe in these applications.
Flue Couplig
Furnace
Exhaust Coupling
Furnace
Top Panel
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