W415-0919 / D / 03.27.13
20
Take the building orientation and the presence of
other buildings or other nearby structures into consid-
eration when planning the venting system location.
Certain external structures could create air turbulence
around the vent termination leading to downdrafts and
similar venting problems. In windy and hill locations,
roof venting may improve operations. maximum vent-
ing length is based on 30 mph winds, areas where
higher gusts are dominant it is suggest to shorten the
horizontal vent length.
The vent and combustion air intake shall be installed
so that both are located in the same wind pressure
zone.
DO NOT CONNECT FURNACE TO A CHIMNEY OR FLUE SERvING OTHER APPLIANCES OR A
SOLID FUEL BURNING APPLIANCE.
WARNINg
!
!
horizontal vents should pass through
the exterior wall. Figure 8 shows a stan-
dard horizontal vent detail. Terminate
the vent approximately 8” or more from
the wall.
Exterior vent pipe greater than 24”
should be insulated with ½” insulation
to prevent moisture from freezing within
the pipe and accumulating.
Size the exhaust pipe as specified in
Table 4 - Direct and Non-Direct Vent
Lengths
. This table lists the maximum
allowable length of pipe with respect to
the number of 90° elbows used. For the
purposes of this calculation, one 90°
elbow is equivalent to two 45° elbows.
Avoid locating the terminal in locations
where dripping condensate may cause
problems such as sidewalks, patios,
above planters, near windows where
exhaust gases may cause fogging, etc.
Avoid locating the termination too close
to shrubs and other vegetation. The
condensate may stunt or kill them.
Equivalents:
Short Sweep = 7’ (feet)
long Sweep = 5’ (feet)
45° Elbow = 3’ (feet)
TABLE 4 - DIRECT AND NON-DIRECT vENT LENGTHS
maximum Allowable length of Exhaust or Intake. minimum Vent length 15 ft.
or equivalent.
INPUT
K/Btu/hr
PIPE
SIzE
NUMBER OF 90° ELBOWS
NOTES
0
1
2
3
4
5
6
45
1½
60
55
50 45
40 35 30
1. Count concentric vent
fitting as straight pipe.
2. use medium or long
sweep elbows where
possible.
3. one 90° elbow is
equivalent to two 45°
elbows.
4. For direct vent, the
listed lengths are
allowed for each vent
(intake and exhaust).
5. For non-direct vent,
the listed lengths are al-
lowed for exhaust. The
intake should have a
1½” or 2” snorkel intake
fitting. (Figure 7)
2
75
70
65 60
55 50 45
60
1½
60
55
50 45
40 35 30
2
75
70
65 60
55 50 45
3
100
95
90 85
80 75 70
80
2
50
45
40 35
30 25 20
3
100
95
90 85
80 75 70
100
2
50
45
40 35
30 25 20
3
100
95
90 85
80 75 70
120
3
100
95
90 85
80 75 70
9.1 venT TeRMInaTIon
NOTE
When 1½” or 3” pipe is used, exit the cabinet with 2” pipe. Reduce or
increase immediately after exiting the cabinet on both intake and exhaust.
*3”
MIN.
12” MIN.
INTAKE
EXHAUST
GRADE
RECOMMENDED
*18” MIN. FOR COLD CLIMATES
(SUSTAINED 0°F (-17°C) FOR
24 OR MORE CONSECUTIVE HOURS
FIGURE 8 - STANDARD (STRAIGHT) HORIzONTAL
vENT DETAIL
