Part number 550-143-010/1021
36
GV90+
series
2
gas-fired water boiler – boiler manual
Figure 42
Combustion and ventilation air openings for GV90+ Direct Vent installations
The GV90+ boiler CANNOT be in the same space with other appliances if clearances around the GV90+ are less than
the recommended service clearances shown in
Air openings
The required air opening sizes below are FREE AREA,
after reduction for louver obstruction. Note the ex-
ception below for large spaces.
GV90+ boiler
WITH other
appliances in room
GV90+ boiler
WITHOUT other
appliances in room
TWO
openings, each at least:
1
square inch per
1,000
Btuh
of all other appliances in the room
NO
openings are required if the boiler instal-
lation provides at least the recommended
If the space is smaller than
, provide openings
ONLY as shown on
.
TWO
openings, each at least:
1
square inch per
4,000
Btuh
of all other appliances in the room
— OR —
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
— OR —
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
— OR —
ONE
opening **, each at least:
1
square inch per
3,000
Btuh
of all other appliances in the room
** NOTICE:
Requirements for using the SINGLE air opening
option.
A single combustion air opening can be used for cases b, c or d above (GV90+ with other appliances in
room only), 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.
SPECIAL EXCEPTION FOR LARGE SPACES
(GV90+ WITH other appliances in room only):
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 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).
DIRECT VENT — Boiler room air openings