Legend LB 1000, Installation Operation & Maintenance

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or spaces freely communicating with the outdoors. The
installation instructions for confined spaces in tightly constructed
buildings must be followed to ensure adequate air supply.
CONFINED SPACE
A. U.S. INSTALLATIONS
When drawing combustion and dilution air from inside a
conventionally constructed building to a confined space, such a
space shall be provided with two permanent openings, ONE IN
OR WITHIN 12 INCHES (305 MM) OF THE ENCLOSURE TOP
AND ONE IN OR WITHIN 12 INCHES (305 MM) OF THE
ENCLOSURE BOTTOM. Each opening shall have a free area of
at least one square inch per 1000 Btu/hr (2,225 mm
2 per kw) of
the total input of all appliances in the enclosure, but not less than
100 square inches (645 cm
2 ).
If the confined space is within a building of tight construction, air
for combustion, ventilation and draft hood dilution must be
obtained from outdoors. When directly communicating with the
outdoors or communicating with the outdoors through vertical
ducts, two permanent openings, located in the aforementioned
manner, shall be provided. Each opening shall have a free area
of not less than one square inch per 4000 Btu/hr (551 mm
2
per
kw) of the total input of all appliances in the enclosure. If horizontal
ducts are used, each opening shall have a free area of not less
than one square inch per 2000 Btu/hr (1,101 mm
2 per kw) of the
total input of all appliances in the enclosure.
B. CANADIAN INSTALLATIONS
Ventilation of the space occupied by the boiler(s) shall be provided
by an opening for ventilation air at the highest practical point
communicating with outdoors. The total cross-sectional area
shall be at least 10% of the area of the combustion air opening
but in no case shall the cross-sectional area be less than
10 square inches (6500 mm
2
).
In addition to the above, there shall be permanent air supply
opening(s) having a cross-sectional area of not less than 1 square
inch per 7,000 BTUH (315 mm
2
/KW) up to and including 1,000,000
BTUH plus 1 square inch per 14,000 BTU (158 mm2/kW) in
excess of 1,000,000 BTUH. This opening(s) shall be located at,
or ducted to, a point neither more than 18” (457 mm) nor less
than 6 inches (152 mm) above the floor level.
Where power vented equipment is used in the same room as the
boiler, sufficient air openings must be supplied.
UNDERSIZED OPENINGS MAY RESULT IN INSUFFICIENT AIR
FOR COMBUSTION.
Where an exhaust fan is installed in the same room with the
boiler, sufficient openings for air must be provided in the walls.
UNDERSIZED OPENINGS WILL CAUSE AIR TO BE DRAWN INTO
THE ROOM THROUGH THE CHIMNEY OR OTHER OPENINGS,
CAUSING POOR COMBUSTION. SOOTING MAY RESULT WITH
AN INCREASED RISK OF ASPHYXIATION.
VENTING
WARNING
THE INSTRUCTIONS IN THIS SECTION ON VENTING THE BOILER
MUST BE FOLLOWED TO AVOID CHOKED COMBUSTION OR
RECIRCULATION OF FLUE GASES. SUCH CONDITIONS CAUSE
SOOTING OR RISKS OF FIRE AND ASPHYXIATION.
VENT SIZING, INSTALLATION AND TERMINATION SHALL BE IN
ACCORDANCE WITH THIS INSTALLATION MANUAL.
ALL ELECTRICAL POWER AND GAS MUST BE TURNED OFF
PRIOR TO ANY INSTALLATION OF THE VENTING SYSTEM.
SPECIAL INSTALLATION CONSIDERATIONS
The Legend 2000 ® is listed as a Category IV appliance and utilizes
a mechanical forced draft system. The vent system shall be
designed to prevent leakage of flue gases and condensate. The
condensate must be allowed to flow to a suitable drain. Since
the condensate is known to be detrimental to conventional vent
materials (galvanized steel, some stainless steels), the vent
material for the boiler’s exhaust shall be approved and certified
for the venting of low temperature condensing flue gasses. AL
29-4C
® is one such material.
The exhaust gases of this boiler are generally only 15°-20°F (8°C
to 11°C) higher than the boiler’s operating temperature, much
lower than a standard boiler. In cold climates any water vapor
remaining in the flue gases will condense into a cloud of vapor at
the point where the vent system exits the building. Special
FIGURE 8. SIDEWALL EXHAUST VENTING