with enclosed draft diverter (no open flue collar). Heaters shall have
minimum steady state thermal efficiencies of 80 percent at maximum rated
capacity and 75 percent at minimum rated capacity that is provided and
allowed by the controls. Heaters shall be provided with a space thermostat
which controls both unit's fan and burner.
2.3.4
Wall Furnace
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NOTE: ANSI Z21.49 defines the gravity type units
which are designed to draw combustion air from
within the space. Indicate on the drawings the type
of air discharge; top or front.
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Wall furnace shall be the [gravity] [fan] type in accordance with ANSI
Z21.49 and as indicated. Furnace shall have a minimum thermal efficiency
of 77 percent. Furnace shall be provided with a space thermostat which
controls both the unit's fan and burner.
2.3.5
Duct Furnace
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NOTE: Aluminized steel heat exchangers will be
satisfactory in most applications. Omit the
aluminized steel if there is a corrosive condition.
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Duct furnace shall be in accordance with ANSI Z83.8. Furnace shall be
power-vented type, suitable for sidewall vent discharge and single wall
thickness vent piping. Furnace shall have automatic ignition. Furnace
shall employ metered combustion air with enclosed draft diverter (no open
flue collar). Furnace heat exchangers shall be [aluminized steel] [or]
[stainless steel]. Furnace shall have minimum steady state thermal
efficiency of 80 percent at maximum rated capacity and 75 percent at
minimum rated capacity that is provided and allowed by the controls.
Furnace shall be provided with a [space] [discharge air] thermostat which
controls the unit's burner.
2.3.6
Infrared Heaters
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NOTE: Unvented infrared heaters may be employed
only in buildings with high ceilings such as shop
buildings, industrial buildings, etc. Exhaust vents
will not be located directly above infrared heaters.
The location of the heaters should be coordinated
with light fixtures, sprinkler systems, structural
members, and any other items that may be sensitive
to the heat that will be generated. Where the units
are used in metal buildings, the roof will be
insulated and an adequate noncombustible vapor
barrier will be provided. Unvented infrared heaters
will not be used in hazardous areas. Select type of
heater required and delete the inapplicable type of
ventilation. Capacity of the exhaust system must be
a minimum of 6.4 liters per second per 1000 Watt
hour (4 cfm per 1,000 Btu per hour) input to
properly dilute the carbon dioxide produced.
SECTION 15565A
Page 9
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