Installation guide

water &oplets. These droplets may be undesirable_ and a 12oiu
mininmm offset pipe section is recommended, as shown in Fig. 35,
to reduce excessive droplets from exiting vent pipe outlet.
CombustionoAir and Vent Pipe Diameter
Determine combustionoair and vent pipe diameter.
1. Using Table 7, individually determine the smallest
combustionoair and vent pipe diameters. Pick the larger of
these 2 pipe diameters and use this diameter tbr both
combustionoair and vent pipes.
2. When installing vent systems of short pipe tengd_, use the
smallest allowable pipe diameter. Do not use pipe size greater
than required or incomplete combustion, flame disturbance, or
flame sense lockout may occur.
NOTE: Do not count elbows or pipe sections in tem_inations or
within Nrnace. See shaded areas in Fig. 37, 38, 39, 40, and 41.
EXAMPLE:
An 080-14 size f:m_lace located in Indianapolis, elcvation
650 ft above sea level, could be installed in an application
requiring 3 elbows and 17 ft of vent pipe, along with 5
elbows and 16 ft of congbustionoair pipe. Table 6 indicates
this application would allow a l-li2-in dianreter veut pipe,
but require a 2Din. diameter combustion air pipe (loli2oin.
pipe is good fbr 20 ft with 3 elbows, but only 10 ft with 5
elbows) Therefbre, 2Din diameter pipe must be used for
both vent and combustionoair pipes since larger required
diameter must always be used fbr both pipes. If same
installation were in Albuquerque, elevation 5250 ft above
sea level, installation would require 2-in. vent pipe and
combustion-air pipe. At 500Io to d000oft elevation, 1ol/2o
in. pipe is not allowed with 5 elbows, but 2-in. pipe is good
for 68 ft with 5 elbows.
(ombustion-Air and Vent Pipe Attachment
NOTE: All pipe joint._; must be cemented except attachmeut of
combustion-air pipe to iulet housing connection since it may be
necessary to remove pipe for servicing.
1. Attach combustion-air pipe as fbllows:
VENT
:--12r'M'N H
PIPE _1 I _,f COMIUSTI_-AIR PIPE
HORIZONTAL TO ROOF
_12" MIN -__
VENT PIPE --_
COMBUSTION-AIR PIPE
HORIZONTAL TO SIDEWALL
COMBUSTION-AIR
PIPE --_
:_ 12" MIN-_B--
COMBUSTION-AIR PIPE _,
f VENT PIPE
12" MIN
VENT PIPE
VERTICALTO ROOF VERTICAL TO SIDEWALL
NOTE: A 12 In. minimum offset pipe section is recommended with
short (5 to 8 ft) vent systems. This recommendation is to reduce
excessive condensate droplets from exiting the vent pipe.
Fig. 3g--Short Vent (5 to 8 Ft) System
3O
A96230