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F97CMN and G97CMN: Installation, Start-up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
8
areas, the combustion air pipe must terminate outdoors as a Direct Vent/
2-Pipe system.
All air for combustion is piped directly to the furnace from a space that is
well ventilated with outdoor air (such as an attic, crawl space, or
equipment closet) and the space is well isolated from the living space or
garage. In addition, other gas appliances installed in the space with the
furnace may require outside air for combustion. Follow the guidelines
below to ensure that the roof or crawlspace walls have sufficient free
area to provide sufficient air for combustion and ventilation for the
furnaces. The guidelines below can be used to ensure that other gas
appliances have sufficient air for combustion.
Provisions for adequate combustion, ventilation, and dilution air must be
provided in accordance with:
• U.S.A. Installations: Section 9.3 of the current edition of NFPA
54/ANSI Z223.1, Air for Combustion and Ventilation and applicable
provisions of the local building codes.
• Canada: Part 8 of the current edition of CAN/CSA-B149.1, Venting
Systems and Air Supply for Appliances.
Outdoor Combustion Air Method
1. Provide the space with sufficient air for proper combustion,
ventilation, and dilution of flue gases using permanent horizontal or
vertical duct(s) or opening(s) directly communicating with the
outdoors or spaces that freely communicate with the outdoors.
2.
illustrates how to provide TWO OUTDOOR OPENINGS,
one inlet and one outlet combustion and ventilation air opening, to
the outdoors.
a. One opening MUST commence within 12 in. (300 mm) of the
ceiling and the second opening MUST commence within 12 in.
(300 mm) of the floor.
b. Size openings and ducts per
and
.
c. TWO HORIZONTAL DUCTS require 1 sq. in. (645 sq. mm) of
free area per 2,000 Btuh (1,100 mm2/kW) of combined input for
all gas appliances in the space per
and
d. TWO OPENINGS OR VERTICAL DUCTS require 1 sq. in.
(645 sq. mm) of free area per 4,000 Btuh (550 mm2/kW) for
combined input of all gas appliances in the space per
3. ONE OUTDOOR OPENING requires:
a. 1 sq. in. (645 sq. mm) of free area per 3,000 Btuh (734 mm2/kW)
for combined input of all gas appliances in the space per
and
b. Not less than the sum of the areas of all vent connectors in the
space.
The opening shall commence within 12 in. (300 mm) of the ceiling.
Appliances in the space shall have clearances of at least 1 in. (25 mm)
from the sides and back and 6 in. (150 mm) from the front. The opening
shall directly communicate with the outdoors or shall communicate
through a vertical or horizontal duct to the outdoors or spaces (crawl or
attic) that freely communicate with the outdoors.
Table 3 – Minimum Free Area Required for Each Combustion Air Opening or Duct to Outdoors
* Not all families have these models.
EXAMPLES: Determining Free Area
CAUTION
!
FURNACE CORROSION HAZARD
Failure to follow this caution may result in furnace damage.
Air for combustion must not be contaminated by halogen compounds,
which include fluoride, chloride, bromide, and iodide. These elements
can corrode heat exchangers and shorten furnace life. Air contaminants
are found in aerosol sprays, detergents, bleaches, cleaning solvents,
salts, air fresheners, and other household products.
WARNING
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal injury or death.
The operation of exhaust fans, kitchen ventilation fans, clothes dryers,
attic exhaust fans or fireplaces could create a NEGATIVE PRESSURE
CONDITION at the furnace. Make-up air MUST be provided for the
ventilation devices, in addition to that required by the furnace. Refer to
the Carbon Monoxide Poisoning Hazard warning in the venting section
of these instructions to determine if an adequate amount of make-up air
is available.
FURNACE INPUT
(BTUH)
TWO HORIZONTAL DUCTS
(1 SQ. IN./2,000 BTUH)
(1,100 SQ. MM/KW)
SINGLE DUCT OR OPENING
(1 SQ. IN./3,000 BTUH)
(734 SQ. MM/KW)
TWO OPENINGS OR
VERTICAL DUCTS
(1 SQ. IN./4,000 BTUH)
(550 SQ. MM/KW)
Free Area of
Opening and Duct
Sq. In (Sq. mm)
Round Duct
In. (mm) Dia
Free Area of
Opening and Duct
Sq. In (Sq. mm)
Round Duct
In. (mm) Dia
Free Area of
Opening and Duct
Sq. In (mm)
Round Duct
In. (mm) Dia.
40,000*
20 (12904)
5 (127)
14 (8696)
5 (127)
10 (6452)
4 (102)
60,000
30 (19355)
6 (152)
20 (13043)
5 (127)
15 (9678)
5 (127)
80,000
40 (25807)
7 (178)
27 (17391)
6 (152)
20 (12904)
5 (127)
100,000
50 (32258)
8 (203)
34 (21739)
7 (178)
25 (16130)
6 (152)
120,000
60 (38709)
9 (229)
40 (26087)
7 (178)
30 (19355)
6 (152)
140,000*
70 (45161)
10 (254)
47 (30435)
8 (203)
35 (22581)
7 (178)
FURNACE
WATER HEATER
TOTAL INPUT
100,000
+
30,000
=
(130,000 divided by 4,000)
=
32.5 Sq. In. for each two Vertical Ducts or Openings
60,000
+
40,000
=
(100,000 divided by 3,000)
=
33.3 Sq. In. for each Single Duct or Opening
80,000
+
30,000
=
(110,000 divided by 2,000)
=
55.0 Sq. In. for each two Horizontal Ducts