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GENERAL VENTING REQUIREMENTS AND
NON-DIRECT VENT (cont.)
(crawl or attic) that freely communicate with the outdoors,
and shall have a minimum of:
A. 1 Square inch for each 3,000 BTUH of the total input rat-
ing of all equipment located in the enclosure
and
B. Not less than the sum of the areas of all vent connectors
in the confined space.
If the unit is installed where there is an exhaust fan, sufficient
ventilation must be provided to prevent the exhaust fan from cre-
ating negative pressure.
Combustion air openings must not be restricted in any manner.
Figure 16 shows allowable inlet air configurations for fur-
naces installed with non-direct vent.
IMPORTANT: When indoor combustion air is used, the
inlet air opening at the furnace must be protected from ac-
cidental blockage (see Figure 16).
DO NOT USE VENT TERMINATIONS WHICH ARE
NOT SPECIFIED IN THESE INSTRUCTIONS. USING
VENT TERMINATIONS OTHER THAN THOSE SPECI-
FIED HERE CAN RESULT IN ERRATIC OPERATION,
EQUIPMENT FAILURE OR PERSONAL INJURY OR
DEATH FROM CARBON MONOXIDE POISONING.
NON-DIRECT VENTING
TERMINATIONS
These furnaces are design-certified to use a single vent
pipe where all combustion air is taken from indoors and
can be vented either vertically or horizontally.
FIGURE 17
VENT PENETRATIONS FOR NON-DIRECT VENT FURNACES
ALL VENT INSTALLED THROUGH UNCONDI-
TIONED SPACE WHERE BELOW-FREEZING TEM-
PERATURES ARE EXPECTED SHOULD BE
INSULATED WITH APPROVED INSULATION MATE-
RIAL. MATERIAL SUCH AS ARMAFLEX OR RUBA-
TEX INSULATION MAY ALSO BE USED AS LONG
AS THERE IS NO HEAT TAPE IS APPLIED TO THE
VENT PIPE. FAILURE TO INSULATE THE PIPE
COULD RESULT IN FREEZING OF WATER IN THE
PIPE THEREBY BLOCKING THE PIPE AND PRE-
VENTING FURNACE OPERATION.
OPTION 1: VERTICAL TERMINATION
Figure 17 shows a standard non-direct vertical vent termi-
nation with clearances.
OPTION 2: STANDARD HORIZONTAL TERMI-
NATION
Figure 18 shows the standard non-direct vent horizontal
termination with minimum clearances.
VENT PENETRATIONS FOR NON-DIRECT VENT FURNACES
WALL PENETRATIONS
NOTE: 3 Ø pipe must
be reduced to 2 Ø pipe
before penetrating roof.
Install inner coupling
Maintain 12" (31cm)
slightly away from
minimum clearance
wall to allow for
above highest
possible thermal
anticipated snow level.
expansion and
For Canadian installa-
contraction.
tions, terminations must
conform to CSA B149.1-
10, Sect. 8.14.
NOTE: If 3 Ø pipe is
used it must be re-
Terminations more
than 24" above roof
duced to 2 Ø before
penetrating wall.
penetration require
additional support.
ST-A1194-19
FIG B
GUIDELINES
FIGURE 18
Couplings:
Required on exterior,
optional on interior.
8" MIN.
12" MAX.
20-31cm
12"/31cfm above grade
or avg. anticipated
snow level. For Cana-
terminations must
B149.1-10, Sect. 8.14.
ST-A1194-19 FIG F
dian installations,
conform to CSA
55
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