Vent Piping Guidelines - Lennox EL296UHE Installation Instructions Manual

Resize the common venting system to the minimum
vent pipe size determined by using the appropriate
tables in Appendix G. (These are in the current stan­
dards of the National Fuel Gas Code ANSI Z223.1.
CHIMNEY
OR GAS
VENT
(Check sizing
for water
heater only)
FURNACE
(Replaced
by EL296)
If an EL296UHE furnace replaces a furnace which
was commonly vented with another gas appliance,
the size of the existing vent pipe for that gas ap­
pliance 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 21
Exhaust Piping (Figures 22, 24 and 25)
Route piping to outside of structure. Continue with installa­
tion following instructions given in piping termination sec­
tion.
CAUTION
Do not discharge exhaust into an existing stack or
stack that also serves another gas appliance. If verti­
cal discharge through an existing unused stack is re­
quired, 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 pres­
sure and must be completely sealed to prevent leak­
age of combustion products into the living space.
REPLACING FURNACE THAT
WAS PART OF A COMMON
VENT SYSTEM
WATER
HEATER
OPENINGS
(To Adjacent
Room)
Page 15

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
®
InnoFlue by Centrotherm venting system the vent pipe re­
quirements stated in the unit installation instruction – min­
imum & maximum vent lengths, termination clearances,
etc. – apply and must be followed. Follow the instructions
provided with PoyPro by DuraVent and InnoFlue by Cen­
trotherm venting system for assembly or if requirements
are more restrictive. The PolyPro by Duravent and In­
noFlue by Centrotherm venting system must also follow
the uninsulated and unconditioned space criteria listed in
table 7.
The EL296UHE can be installed as either a Non-Direct
Vent or a Direct Vent gas central furnace.
NOTE - In Non‐Direct Vent installations, combustion air is
taken from indoors or ventilated attic or crawlspace and
flue gases are discharged outdoors. In Direct Vent installa­
tions, combustion air is taken from outdoors and flue gases
are discharged outdoors.
Intake and exhaust pipe sizing -- Size pipe according to
tables 3 and . Count all elbows inside and outside the
5
home. Table 3 lists the minimum vent pipe lengths per­
mitted. Table lists the maximum pipe lengths permitted.
5
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 velocity of the exhaust gas as it
exits the termination. Refer to table 8.
In some applications which permit the use of several differ­
ent 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.
NOTE - The exhaust collar on all models is sized to accom­
modate 2" Schedule 40 vent pipe. In horizontal applica­
tions, any transition to exhaust pipe larger than 2" must be
made in vertical runs of the pipe. Therefore a 2" elbow must
be added before the pipe is transitioned to any size larger
than 2". This elbow must be added to the elbow count used
to determine acceptable vent lengths. Contact the Applica­
tion Department for more information concerning sizing of
vent systems which include multiple pipe sizes.
®
and
®
by DuraVent or