Table of Contents
Advertisement
Concentric vent termination
kits are available for use
with these furnaces. For 2 Inch pipe use kit #904177
and for 3 inch pipe use kit # 904176. Please follow the
instructions provided with the kit.
, When the vent pipe must exit an exterior wall close to
the grade or expected snow level where it is not possible
to obtain clearances shown in Figure 6, a riser may be
provided as shown in Figure 8. insulation is required
to prevent freezing of this section of pipe. See Table 3
for vent freezing protection.
Outdoor Terminations
- Vertical Venting
Termination spacing requirements from the roof and from
each other are shown in Figure 9. The roof penetration
must be properly flashed and waterproofed with a plumbing
roof boot or equivalent flashing. Vent and combustion air
piping may be installed in an existing chimney which is
not in use provided that:
Both the exhaust vent and air intake run the length of
the chimney.
Mechanical
vent terminal
NOTES:
1. All dimensions shown are
minimum requirements.
2. Exterior vent terminations
must
be located at least 12" above the
maximum expected snow level.
Forced air inlet
Direct vent
terminal - more
than 50,000 Btuh
Figure 7. Vent Locations
19" Max.
(See Note)
I.<-........._
12" Above
Maximum
Expected
Support
j
Snow Level
Outside--,.-
/4.. _ 1/2
Wall
_ _ Armaflex
_. i_ Insulation
or
o-_
_/_
Equivalent
NOTE:
Vent Configuration
to Provide
12" Minimum
height
above
Snow
Level.
The top of the chimney is sealed and weatherproofed.
The termination
clearances
shown in Figure 9 are
maintained.
No other gas fired or fuel-burning equipment is vented
through the chimney.
Vent Freezing Protection
/!X CAUTION'.
When the vent pipe is exposed
to temperatures
below
freezing
(i.e., when
it passes
through
unheated
spaces,
chimneys,
etc.)
the
pipe
must
be insulated
with 1/2 inch thick
sponge
rubber
insulation,
Armaflex=type
insulation
or
equivalent,
insulating
pipe is important
to avoid
condensate
icing.
Table 3 lists the maximum length of flue pipe that can
travel through an unconditioned space or an exterior
space. The total vent length must not exceed the lengths
noted in Table 2 (page 11). For Canadian installations,
please refer to the Canadian Installation Code (CAN/
CGA-B149.1 or 2) and/or local codes.
For extremely cold climates or for conditions of short
furnace cycles (i.e. set back thermostat
conditions)
the last 18 inches of vent pipe can be reduced. It is
acceptable to reduce from 3" to 2-1/2", 3" to 2", or 2"
to 1-1/2" if the total vent length is at least 15 feet in
length and the vent length is within the parameters
specified in Table 2 (page 11). The restriction should
be counted as 3 equivalent feet. Smaller vent pipes are
Maximum Flue Pipe Length (FEET)
Winter Design
n Unconditioned
& Exterior
Spaces
Temperature
Without insulation
With insulation*
20
45
70
0
20
70
-20
10
60
*NOTE: Insulation thickness greater than 3/8 inch, based on an
R value of 3.5 (ftx F x hr) / (BTU x in.)
Table 3. Vent Protection
Elbows on the combustion
air
inlet must be positioned
away from the exhaust vent.
Plumbing Vent Roof Boot
(Both Pipes)
Expected Snow
(Both pipes)
Figure 8. Alternate Horizontal Vent Installation
Figure 9. Vertical Vent Termination
13
Advertisement
Table of Contents
