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926SA: Installation, Start-up, Operating, Service and Maintenance Instructions
2. The air infiltration rate is not known to be less than 0.40 air changes
per hour (ACH).
The Known Air Infiltration Rate Method shall be used, if the infiltration
rate is known to be:
1. Less than 0.40 ACH and
2. 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 4
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.
Table 4
- Minimum Space Volumes were determined by using the
following equations from the current edition of the National Fuel Gas
Code ANSI Z223.1/NFPA 54, 9.3.2.2:
1. For other than fan-assisted appliances, such as a draft
hood-equipped water heater:
= 21ft
Volume
Other
2. For fan-assisted appliances such as this furnace:
= 15ft
Volume
Fan
I
If:
other = combined input of all other than fan-assisted appliances in
Btuh/hr.
I
fan = combined input of all fan-assisted appliances in Btuh/hr
ACH = air changes per hour (ACH shall not exceed 0.60.)
The following requirements apply to the Standard Method and to the
Known Air Infiltration Rate Method.
1. Adjoining rooms can be considered part of a space if:
a. There are no closeable doors between rooms.
b. Combining spaces on same floor level. Each opening shall have
free area of at least 1 in.2/1,000 Btuh (2,000 mm2/kW) of the
total input rating of all gas appliances in the space, but not less
than 100 in.2 (0.06 m2). One opening shall commence within 12
in. (300 mm) of the ceiling and the second opening shall
commence within 12 in. (300 mm) of the floor. The minimum
dimension of air openings shall be at least 3 in. (80 mm). See
Fig.
7.
c. Combining space on different floor levels. The volumes of
spaces on different floor levels shall be considered as
communicating spaces if connected by one or more permanent
openings in doors or floors having free area of at least 2
in.2/1,000 Btuh (4,400 mm2/kW) of total input rating of all gas
appliances.
2. An attic or crawlspace may be considered a space that freely
communicates with the outdoors provided there are adequate
permanent ventilation openings directly to outdoors having free
area of at least 1-in.2/4,000 Btuh of total input rating for all gas
appliances in the space.
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
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
I
3
other
ACH
1000 Btu/hr
I
3
fan
ACH
1000 Btu/hr
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.
Combination of Indoor and Outdoor Air
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 below.
b. Outdoor opening size reduction Factor is 1 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).
CONDENSATE TRAP
A04002
Condensate Trap - Upflow Orientation
When the furnace is installed in the upflow position, it is not necessary
to relocate the condensate trap or associated tubing. Refer to
upflow condensate trap information. Refer to Condensate Drain section
for information how to install the condensate drain.
A04003
Condensate Trap - Downflow Orientation.
When the furnace is installed in the downflow position, the condensate
trap will be initially located at the upper left corner of the collector box,
as received from the factory. See the top image in
furnace is installed in the downflow orientation, the condensate trap
must be relocated for proper condensate drainage. See the bottom image
in
Fig.
9.
To Relocate the Condensate Trap:
• Orient the furnace in the downflow position.
•
Fig. 9
shows the condensate trap and tubing before and after
relocation. Refer to
• Refer to Condensate Drain section for information how to install the
condensate drain.
Condensate Trap - Horizontal Orientation.
When the furnace is installed in the horizontal right position, the
condensate trap will be initially located at the bottom of the collector
box, as received from the factory. See the top image in
furnace is installed in the horizontal left position, the condensate trap
will be initially located at the top of the collector box, as received from
the factory. See the top image in
repositioned on the collector box for proper condensate drainage. See the
bottom images in
Fig. 10
A field-supplied, accessory Horizontal Installation Kit (trap grommet) is
required for all direct-vent horizontal installations (only). The kit
contains a rubber casing grommet designed to seal between the furnace
casing and the condensate trap. See
9
Fig. 9
to begin the trap conversion.
Fig.
11. In both cases the trap must be
and
Fig.
11.
Fig.
18.
Fig. 8
for
Fig.
9. When the
Fig.
10. When the
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