Weil-McLain SlimFit 2 Series Manual page 31

SlimFit ® Series 2
DIRECT EXHAUST — Boiler room air openings
(Category IV)
Figure 25
MINIMUM combustion air openings for direct exhaust applications — ALL OPENING SIZES ARE FREE AREA
Air openings
The required air opening sizes below are FREE
AREA, after reduction for louver obstruction. Note
the exception below for large spaces.
** NOTICE:
Requirements for using the SINGLE air open-
ing option
SPECIAL EXCEPTION FOR LARGE SPACES:
Part number 550-100-561/0224
commercial condensing gas
appliances in room
TWO
1
TWO
1
ONE
1
TWO
1
ONE
1
TWO
1
ONE
1
A single combustion air opening can be used for cases b, c or d above, sized as listed,
provided that:
• The single opening must communicate directly to the outdoors or to a space that
communicates directly with outdoors (NOT to an interior space).
• The top of the opening must be within 12 inches of the ceiling.
• The free area of the opening must be at least equal to the sum of the areas of all
equipment vent connectors in the space.
NO combustion air openings are needed when the boiler (and other appliances) are
installed in a space with a volume NO LESS than 50 cubic feet per 1,000 Btuh of all
appliances in the space. That is, total the input of all appliances in MBH (1,000's of
Btuh), then multiply this total times 50. The building MUST NOT be of tight construction.
Example: For a total input of 1500 MBH (1,500,000 Btuh) and an 8-foot ceiling height,
the minimum volume would be 50 x 1500 = 75,000 cubic feet.
- — Boiler Manual
fired water boiler
SlimFit boiler
WITH other
openings, each at least:
1,000
square inch per Btuh
of all appliances in the room
openings, each at least:
4,000
square inch per Btuh
of all appliances in the room
— OR —
opening **, each at least:
3,000
square inch per Btuh
of all appliances in the room
openings, each at least:
2,000
square inch per Btuh
of all appliances in the room
— OR —
opening **, each at least:
3,000
square inch per Btuh
of all appliances in the room
openings, each at least:
4,000
square inch per Btuh
of all appliances in the room
— OR —
opening **, each at least:
3,000
square inch per Btuh
of all appliances in the room
(continued)
SlimFit boiler
WITHOUT other
appliances in room
TWO
openings, each at least:
1 4,000
square inch per Btuh
of all appliances in the room
TWO
openings, each at least:
1 4,000
square inch per Btuh
of all appliances in the room
— OR —
ONE
opening **, each at least:
1 3,000
square inch per Btuh
of all appliances in the room
TWO
openings, each at least:
1 4,000
square inch per Btuh
of all appliances in the room
— OR —
ONE
opening **, each at least:
1 3,000
square inch per Btuh
of all appliances in the room
TWO
openings, each at least:
1 4,000
square inch per Btuh
of all appliances in the room
— OR —
ONE
opening **, each at least:
1 3,000
square inch per Btuh
of all appliances in the room
31