Combination Of Indoor And Outdoor Air - International comfort products N9MSE Series Installation Instructions Manual

INSTALLATION INSTRUCTIONS
Air for Combustion, Ventilation,
Figure 7
and Dilution from Indoors
* Minimum opening size is 100 sq in. (64516 sq. mm) with
minimum dimensions of 3‐in. (76mm)
{ Minimum of 3‐in. (76mm) when type‐B1 vent is used.
Table 3 Minimum Free Area Required for Each Combustion Air Opening or Duct to Outdoors
TWO HORIZONTAL DUCTS
(1 SQ. IN./2,000 BTUH)
(1,100 SQ. MM/KW)
FURNACE
INPUT
(BTUH)
Free Area of
Opening and Duct
Sq. In (Sq. mm)
40,000 20 (12904)
60,000 30 (19355)
80,000 40 (25807)
50 (32258)
100,000
120,000 60 (38709)
140,000 70 (45161)
EXAMPLE: Determining Free Area
FURNACE WATER HEATER
100,000 + 30,000
60,000 + 40,000
80,000 + 30,000
440 01 4103 03

Combination of Indoor and Outdoor Air

L12F013
SINGLE DUCT OR OPENING
(1 SQ. IN./3,000 BTUH)
(734 SQ. MM/KW)
Round
Free Area of Open-
Duct
ing and Duct
In. (mm)
Sq. In (Sq. mm)
Dia
5 (127) 14 (8696)
6 (152) 20 (13043)
7 (178) 27 (17391)
8 (203) 34 (21739)
9 (229) 40 (26087)
10 (254) 47 (30435)
TOTAL INPUT
= (130,000 divided by 4,000)
= (100,000 divided by 3,000)
= (110,000 divided by 2,000)
Specifications subject to change without notice.
3. In spaces that use the Indoor Combustion Air Method,
infiltration should be adequate to provide air for
combustion, permanent ventilation and dilution of flue
gases. However, in buildings with unusually tight
construction, additional air MUST be provided using
the methods described in the Outdoor Combustion Air
Method section.
4. Unusually tight construction is defined as Construction
with:
a. Walls and ceilings exposed to the outdoors have a
continuous, sealed vapor barrier. Openings are
gasketed or sealed and
b. Doors and openable windows are weatherstripped
and
c. Other openings are caulked or sealed. These include
joints around window and door frames, between sole
plates and floors, between wall-ceiling joints, between
wall panels, at penetrations for plumbing, electrical
and gas lines, etc.
1. Indoor openings shall comply with the Indoor
Combustion Air Method below and,
2. Outdoor openings shall be located as required in the
Outdoor Combustion Air Method mentioned previously
and,
3. Outdoor openings shall be sized as follows:
a. Calculate the Ratio of all Indoor Space volume
divided by required volume for Indoor Combustion
Air Method.
b. Outdoor opening size reduction Factor is one minus
the Ratio in a. above.
c. Minimum size of Outdoor openings shall be the size
required in Outdoor Combustion Air Method above
multiplied by reduction Factor in b. above. The
minimum dimension of air openings shall be not less
than 3-in. (80 mm).
TWO OPENINGS OR
(1 SQ. IN./4,000 BTUH)
Round
Free Area of Open-
Duct
ing and Duct
In. (mm)
Sq. In (mm)
Dia
5 (127) 10 (6452)
5 (127) 15 (9678)
6 (152) 20 (12904)
7 (178) 25 (16130)
7 (178) 30 (19355)
8 (203) 35 (22581)
= 32.5 Sq. In. for each two Vertical Ducts or Openings
= 33.3 Sq. In. for each Single Duct or Opening
= 55.0 Sq. In. for each two Horizontal Ducts
Gas Furnace: N9MSE
VERTICAL DUCTS
(550 SQ. MM/KW)
Round Duct
In. (mm)
Dia.
4 (102)
5 (127)
5 (127)
6 (152)
6 (152)
7 (178)
11