11
7.
Remove the debris screen (or cover panel for model
1005A) by removing the screws holding it in place.
Debris Screen
Figure 11. Remove the Debris Screen
8. Install the intake air collar using the six screws
removed in Step 7.
Intake Air Collar
Figure 12. Install the Intake Air Collar
9. Replace all the access panels.
10. 1Install ducted air intake piping appropriate for your
installation using PVC, CPVC or sealed single-wall
galvanized ducting. The duct will attach directly to
the field-installed air collar located on the rear of
the heater, using three or four sheet metal screws
(not supplied) equally positioned around the
circumference of the duct.
NOTE:
Make sure that the air intake piping is installed in
a manner that allows full access to the air filter without
damage to the filter.
3.5.5. TruSeal
®
Combustion Air
In addition to the previous steps, the combustion air
system can be sealed to meet Direct Vent requirements
by sealing the mounting screws and duct connection
point with RTV (not supplied). All ducting
MUST
be self-
supported.
A
A
CAUTION:
Use TruSeal combustion air if damaging
airborne contaminants are or may be present in the
heater area. See the Appendix of this manual regarding
air contamination.
3.6. Air Supply
3.6.1. U.S. Installations
All Air from Inside the Building
The confined space shall be provided with TWO
permanent openings communicating directly with
an additional room(s) of sufficient volume so that the
combined volume of all spaces meets the criteria for a
room large in comparison (NFGC). The total input of all
gas utilization equipment installed in the combined space
shall be considered in making this determination.
Each opening shall have a minimum free area of 1 square
inch per 1,000 BTUH (2,225 mm² per kW) of the total input
rating of all gas utilization equipment in the confined
space, but not less than 100 square inches (645 cm²). One
opening shall commence within 12" (305 mm) of the top,
and one opening shall commence within 12" (305 mm)
of the bottom of the enclosure. The minimum dimension
of air openings shall be not less than 3" (76 mm) in any
direction.
All Air from Outdoors
The confined space shall communicate with the outdoors
in accordance with one of the methods below. The
minimum dimension of air openings shall not be less than
3" (76 mm) in any direction. Where ducts are used, they
shall be of the same cross-sectional area as the net free
area of the openings to which they connect.
1. Two permanent openings,
one commencing within
12" (305 mm) of the top, and one commencing within
12" (305 mm) of the bottom of the enclosure, shall be
provided. The openings shall communicate directly,
or by ducts, with the outdoors or spaces (crawl or
attic) that freely communicate with the outdoors.
a. Where directly communicating with the
outdoors or where communicating to the
outdoors through vertical ducts,
each opening
shall have a minimum free area of 1 square inch
per 4,000 BTUH (550 mm² per kW) of total input
rating of all equipment in the enclosure.
