269441-UIM-A-0407
Unitary Products Group
19
VERTICAL VENT APPLICATIONS AND
TERMINATION
Roof mounted vertical terminals may be field fabricated. Standard PVC/
SRD fittings may be used. If installing a vertical venting system through
any unconditioned space such as an attic or crawl space it must be
insulated.
1.
Observe all clearances listed in vent clearances in these instruc-
tions.
2.
Termination should be positioned where vent vapors are not objec-
tionable.
3.
Termination should be located where it will not be affected by wind
gusts, light snow, or allow recirculation of flue gases.
4.
Termination should be located where it cannot be damaged,
plugged or restricted by tree limbs, leaves and branches.
5.
Horizontal portions of the vent system must slope upwards and be
supported to prevent sagging. The vent system may be supported
by the use of clamps or hangers secured to a permanent part of
the structure every 4 ft. (1.22 m).
VENTING MULTIPLE UNITS
Only the sealed combustion system can be used for installations requir-
ing more than one furnace in a structure. A separate sealed combustion
air pipe and a separate vent pipe must be installed for each furnace. Do
not connect more than one furnace to a combustion air pipe or a vent
pipe. The combustion air and vent termination must be located as
shown in Figures 23 or 24.
COMBUSTION AIR SUPPLY
All installations must comply with Section 5.3, Air for Combustion and
Ventilation of the National Fuel Gas Code, ANSI Z223.1 or Sections
7.2, 7.3 or 7.4 of CAN/CGA B149.1 or .2 Installation Code - latest edi-
tions.
This furnace is certified to be installed with one of three possible com-
bustion air intake configurations.
1.
OUTDOOR COMBUSTION AIR:
This is a sealed combustion air
configuration where the combustion air is supplied through a PVC
or ABS pipe that is connected to the PVC coupling attached to the
burner box and is terminated in the same atmospheric zone as the
vent. This type of installation is approved on all models. Refer to
Figures 25 & 27.
2.
AMBIENT COMBUSTION AIR:
Combustion air is supplied from
the area surrounding the furnace through the combustion air pipe
in the furnace casing. The combustion air and the vent pipes are
not terminated in the same atmospheric zone. Refer to Figures 19
& 26 for vent terminations. Refer to “AMBIENT COMBUSTION
AIR SUPPLY” and “VENT AND SUPPLY OUTSIDE AIR SAFETY
CHECK PROCEDURE” for proper installation.
3.
VENTILATED COMBUSTION AIR:
Combustion air is supplied
through a PVC or ABS pipe that is connected to the PVC coupling
attached to the burner box and is terminated in a ventilated attic or
crawl space. The combustion air and the vent pipes are not termi-
nated in the same atmospheric zone. Refer to Figure 28 for crawl
space and attic termination. Only the combustion air intake may
terminate in the attic. The vent must terminate outside.
Outdoor Combustion Air
Combustion Air Intake/Vent Connections
This installation requires combustion air to be brought in from outdoors.
This requires a properly sized pipe (shown in Figures 31, 33, or 35) that
will bring air in from the outdoors to the furnace combustion air intake
collar on the burner box. The second pipe (shown in Figures 31, 33 or
35) is the furnace vent pipe.
FIGURE 22:
Crawl Space Termination Configuration - 2Pipe
FIGURE 23:
Double Horizontal Sealed Combustion Air and Vent
Termination
12” MINIMUM
BELOW
OVERHANG
12”
SEPARATION
BETWEEN BOTTOM
OF COMBUSTION
AIR PIPE AND
BOTTOM OF VENT
MINIMUM
MAINTAIN 12”
MINIMUM CLEARANCE
ABOVE HIGHEST
ANTICIPATED SNOW
LEVEL OR GRADE,
WHICHEVER IS
HIGHER
VENT DRAIN
VENT
2”
MIN.
COMBUSTION AIR
FIGURE 24:
Double Vertical Sealed Combustion Air and Vent
Termination
FIGURE 25:
Sealed Combustion Air Intake Connection and Vent
Connection
MIN.
6”
2” (5.08 cm)
VENT
CONNECTION
AIR INTAKE
