Carrier DIRECT VENT 4 58HDV Installation Instructions Manual page 10

Table 1
Free Area
BTUH (kW)
Two Horizontal Ducts
Input Rating
sq. in./2,000(1 cm
40,000 (11.72) 20 sq. in. (129 cm
50,000 (14.65) 25 sq. in. (161 cm
60,000 (17.58) 30 sq. in. (194 cm
75,000 (21.98) 37.5 sq. in. (242 cm
80,000 (23.45) 40 sq. in. (258 cm
100,000 (29.31) 50 sq. in. (322 cm
125,000 (36.63) 62.50 sq. in. (403 cm
EXAMPLE: Determining Free Area
Furnace Water Heater
100,000 +
29.31
Furnace Water Heater
100,000
+
29.31
Indoor Combustion Air (Unconfined Space)
WARNING
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal injury
or death.
Most homes will require additional air from outdoors for
combustion and ventilation. A space with at least 50 cubic feet
3 2
(1.4 M) per 1,000 (2.33 cm
with tight construction may need outdoor air, supplied through
ducts, to supplement air infiltration for proper combustion and
ventilation of flue gasses.
Standard and Known- Air- Infiltration Rate Methods
© NFPA & AGA
Indoor air is permitted for combustion and ventilation, if the
Standard or Known- -Air- -Infiltration Rate Method is used.
The Standard Method may be used, if the space has no less
volume than 50 cubic feet per 1,000 BTUH input rating for all gas
MINIMUM SPACE VOLUME FOR 100% COMBUSTION AND VENTILATION AIR FROM INDOORS
Table 2
30,000 BTU
(8,790 kW)
ACH
0.60 1,050 (29.7)
0.50 1,260 (35.3)
0.40 1,575 (44.1)
0.30 2,100 (58.8)
0.20 3,150 (88.2)
0.10 6,300 (176.4)
0.00 NP
ACH = Air Changes per Hour
NP = Not Permitted
Table 2 Minimum Space Volumes were determined by using the following equations from the National Fuel Gas Code ANSI Z223.1/NFPA 54 ---2006, 9.3.2.2:
1. For appliances other than fan- -assisted appliances (such as
a draft hood- -equipped water heater), calculate using the fol-
lowing equation:
Minimum Free Area Required for Each Opening or Duct to Outdoors
BTUH (kW)
2
/.09) sq. in./3,000 (1 cm
2
)
2
)
2
)
2
)
2
)
2
)
2
)
30,000 =
8.8
30,000
=
8.8
/kW) Btuh Input rating or homes
Other Than Fan- Assisted Total
40,000 BTU 50,000 BTU
(11,720 kW) (14,650 kW)
1,400 (39.2) 1,750 (49)
1,680 (47.04) 2,100 (58.8)
2,100 (58.8) 2,625 (73.5)
2,800 (78.4) 3,500 (98)
4,200 (117.6) 5,250 (147)
8,400 (235.2) 10,500 (294)
NP
Single Opening
BTUH (kW)
2
/.135)
2
13.34 sq. in. (86 cm )
2
16.7 sq. in. (108 cm )
2
20 sq. in. (129 cm )
2
25 sq. in. (161 cm )
2
26.7 sq. in. (172 cm )
2
33.3 sq. in. (215 cm )
2
41.7 sq. in. (269 cm )
Total Input
(130,000 ÷ 4,000)
(38.11 ÷ .18)
Total Input
(130,000 ÷ 2,000)
(38.11 ÷ .09)
appliances installed in the space. The standard method permits
indoor air to be used for combustion and ventilation air.
The Known Air Infiltration Rate Method shall be used if the
infiltration rate is known to be less than 0.40 air changes per hour
(ACH) and equal to or greater than 0.10 ACH. Infiltration rates
greater than 0.60 ACH shall not be used. The minimum required
volume of the space varies with the number of ACH and shall be
determined per Table 2 or Equations 1 and 2. Determine the
minimum required volume for each appliance in the space, and add
the volumes together to get the total minimum required volume for
the space.
!
CARBON MONOXIDE POISONING HAZARD
Failure to supply additional air by means of ventilation grilles
or ducts could result in personal injury or death.
An unconfined space or homes with tight construction may
not have adequate air infiltration for proper combustion and
ventilation of flue gasses. Most homes will require additional
air.
50,000 BTU
(14,650 kW) (21,975 kW)
3 3
ft ( )
m
1,250 (35) 1,875 (52.5)
1,500 (42)
1,875 (52.5) 2,813 (78.8)
2,500 (70) 3,750 (105)
3,750 (105) 5,625 (157.5)
7,500 (210) 11,250 (315)
NP NP
Required Volume
10
Two Vertical Ducts or Round Duct
Openings
BTUH (kW)
2
sq. in./4,000(1 cm /.18) in./4,000(6.5cm
2
10 sq. in. (65 cm ) 4" (101.6mm)
2
12.5 sq. in. (81 cm ) 4" (101.6mm)
2
15 sq. in. (97 cm )
2
18.75 sq. in. (121 cm )
2
20 sq. in. (129 cm )
2
25 sq. in. (161 cm ) 6" (152.4mm)
2
31.25 sq. in. (202 cm ) 7" (177.8mm)
= 32.5 Sq. In. Vertical
2
m
= 210 c Vertical
= 65 Sq. In. Horizontal
2
cm
= 423 Horizontal
WARNING
Fan- assisted Total
75,000 100,000 BTU
(29,300 kW)
2,500 (70)
2,250 (63) 3,000 (84)
3,750 (105)
5,000 (140)
7,500 (210)
15,000 (420)
NP NP
(
I
3
21 ft
²
other
1000 Btu / hr
ACH
BTUH (kW)
sq.
2
/.18)
5" (127mm)
5" (127mm)
5" (127mm)
125,000 BTU
(36,625 kW)
3,125 (87.5)
3,750 (105)
4,688 (131.3)
6,250 (175)
9,375 (262.5)
18,750 (525)
NP
)
other