Direct Vent - Boiler Room Air Openings - Williamson-Thermoflo GWC-070 Manual

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DIRECT VENT — Boiler room air openings
Figure 42
Combustion and ventilation air openings for GWC Direct Vent installations
The GWC boiler CANNOT be in the same space with other appliances if clearances around the GWC are less than
the recommended service clearances shown in Figure 2, page 6.
Air openings
The required air opening sizes below are FREE AREA,
after reduction for louver obstruction. Note the ex-
ception below for large spaces.
** NOTICE:
Requirements for using the SINGLE air opening
option.
SPECIAL EXCEPTION FOR LARGE SPACES
(GWC WITH other appliances in room only):
36
-
fired water boiler
appliances in room
TWO openings, each at least:
1 square inch per 1,000 Btuh
of all other appliances in the room
TWO openings, each at least:
1 square inch per 4,000 Btuh
of all other appliances in the room
ONE opening **, each at least:
1 square inch per 3,000 Btuh
of all other appliances in the room
TWO openings, each at least:
1 square inch per 4,000 Btuh
of all other appliances in the room
ONE opening **, each at least:
1 square inch per 3,000 Btuh
of all other appliances in the room
TWO openings, each at least:
1 square inch per 2,000 Btuh
of all other appliances in the room
ONE opening **, each at least:
1 square inch per 3,000 Btuh
of all other appliances in the room
A single combustion air opening can be used for cases b, c or d above (GWC with
other appliances in room only), sized as listed, provided that:
•
•
•
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 ap-
pliances 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 500 MBH (500,000 Btuh), the minimum volume would be
50 x 500 = 25,000 cubic feet (3,125 square feet if ceiling height is 8 feet).
— Boiler Manual
GWC boiler
WITH other
— OR —
— OR —
— OR —
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.
GWC boiler
WITHOUT other
appliances in room
NO openings are required if the
boiler installation provides at least the
recommended service clearances
shown in Figure 2, page 6.
If the space is smaller than Fig-
ure 2, page 6, provide openings
ONLY as shown on page 7 and
Figure 4, page 7.
Part number 550-142-786/0712