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GSA
Gas-Fired Steam Boilers –
Boiler Manual
6
Part Number 550-110-738/1012
1 Prepare boiler location
continued
Air openings
Place boiler/crate near position
1.
Leave boiler in crate and on pallet until installation site is
ready.
2. Move entire crate and pallet next to selected location.
3. Remove crate.
Leave boiler on pallet.
4. Unbolt boiler from pallet.
5. Remove boiler from pallet.
Provide adequate combustion and ventilation air to
assure proper combustion and reduce the risk of
severe personal injury, death or substantial property
damage caused by flue gas spillage and carbon
monoxide emissions.
Combustion air and ventilation openings must comply with
the National Fuel Gas Code, ANSI Z223.1 – latest edition, or ap-
plicable local building codes. Canadian installations must comply
with B149.1 or B149.2 Installation Codes.
Air opening sizes in the following are given in free area (after
correction for louver obstruction).
Option 1 — Provide (2) openings:
Option 2 — Provide (1) opening:
A single combustion air opening can be used, provided:
• The opening must commence within 12 inches of the ceiling.
• The boiler must have clearances of at least 1 inch from both
sides and back, and 6 inches from the front.
• The opening must connect directly to the outdoors or to a
space that communicates directly to the outdoors.
• The air can be provided through a direct opening or through
a horizontal or vertical duct.
• The free area of the opening must be at least equal to the
sum of all vent connectors in the space.
• The free area of the opening must be at least 1 square inch
per 3000 Btu/hr input rating of all equipment located in the
space.
Tight construction — Definition:
Tight construction means (per ANSI Z223.1):
• Walls and ceilings exposed to the outside atmosphere have
a continuous water vapor retarder with a rating of 1 perm or
less with openings gasketed. AND
• Weather‑stripping has been added on openable windows and
doors. AND
• Caulking or sealants are applied to areas such as joints
around windows and door frames, between sole plates and
floors, between wall‑ceiling joints, between wall panels, at
penetrations for plumbing, electrical, and gas lines, and in
other openings.
Tight construction requirements
If building is of tight construction and air is taken from inside the
building, provide two openings in building outside wall, one within
12 inches of ceiling, the other within 12 inches of the floor. Each
opening must have a minimum free area of 1 square inch per
1,000 Btuh of all appliances in the building.
Exception
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 installed appliances.
Sum the total input of all appliances in MBH (1,000’s of Btuh)
and multiply this number times 50. Building must not be of Tight
construction (see above).
Example: For total input of 100 MBH (100,000 Btuh), minimum
volume is 50 x 100 = 5,000 cubic feet. At a ceiling height of 8 feet,
space must have at least 5,000 ÷ 8 = 625 square feet (25 feet x
25 feet, for instance).
Exhaust fans and air movers
The appliance space must never be under a negative pressure.
Always provide air openings sized not only to the dimensions
required for the firing rate of all appliances, but also to handle
the air movement rate of the exhaust fans or air movers using air
from the building or space.
Motorized air dampers
If the air openings are fitted with motorized dampers, electrically
interlock the damper to:
• Prevent the boiler from firing if the damper is not fully open.
• Shut the boiler down should the damper close during boiler
operation.
To accomplish this interlock, wire an isolated contact (proving the
damper open) in series with the thermostat input to the boiler. The
boiler will not start if this damper is closed, and will shut down
should damper close during operation.
Placement and setup