5
INSTALLATION
Do not install unit heaters in
corrosive or flammable atmospheres! Premature
failure of, or severe damage to the unit will
result!
Avoid locations where extreme
drafts can affect burner operation. Unit heaters
must not be installed in locations where air for
combustion would contain chlorinated, halo-
genated or acidic vapors. If located in such an
environment, premature failure of the unit will
occur!
Since the unit is equipped with an automatic gas ignition
system, the unit heater must be installed such that the
gas ignition control system is not directly exposed to
water spray, rain or dripping water.
NOTICE: Location of unit heaters is related directly
to the selection of sizes. Basic rules are as follows:
MOUNTING HEIGHT:
Unit Heaters equipped with
standard fan guards must be installed at a minimum of
8 feet (2.4m) above the floor, measured to the bottom
of the unit. At heights above 8 feet (2.4m), less efficient
air distribution will result.
If a unit is to be mounted
below eight (2.4m) from the floor, an OSHA approved
fan guard is required on the unit.
AIRCRAFT HANGARS:
Unit Heaters must be installed
in aircraft hangars as follows: In aircraft hangars, unit
heaters must be at least 10 feet (3.0m) above the upper
surface of wings or engine enclosures of the highest
aircraft to be stored in the hangar, and 8 feet (2.4m)
above the floor in shops, offices and other sections of
the hangar where aircraft are not stored or housed.
Refer to current ANSI/NFPA No. 409, Aircraft Hangars.
In Canada, installation is suitable in aircraft hangars
when acceptable to the enforcing authorities.
PUBLIC GARAGES:
In repair garages, unit heaters
must be at least 8 feet (2.4m) above the floor. In parking
structures, unit heaters must be installed so that the
burner flames are located 18 in. (457mm) above the
floor or protected by a partition not less than 18 in.
(457mm) high. Refer to current NFPA No. 88A, Parking
Structures and NFPA No. 88B, Repair Garages. In
Canada, installation must be in accordance with current
CGA B149 “Installation Codes for Gas Burning
Appliances and Equipment.”
AIR DISTRIBUTION:
Direct air towards areas of
maximum heat loss. When multiple heaters are involved,
circulation of air around the perimeter is recommended
where heated air flows along exposed walls. Satisfactory
results can also be obtained where multiple heaters are
located toward the center of the area with heated air
directed toward the outside walls. Be careful to avoid
all obstacles and obstructions which could impede the
warm air distribution patterns.
Unit heaters should not be installed to maintain low
temperatures and/or freeze protection of buildings.
A minimum of 50
°
F (10
°
C) thermostat setting must
be maintained.
If unit heaters are operated to maintain
lower than 50
°
F (10
°
C), hot flue gases are cooled inside
the heat exchanger to a point where water vapor (a flue
gas by-product) condenses onto the heat exchanger
walls. The result is a mildly corrosive acid that
prematurely corrodes the aluminized heat exchanger
and can actually drip water down from the unit heater
onto floor surface. Additional unit heaters should be
installed if a minimum 50
°
F (10
°
C) thermostat setting
cannot be maintained.
AIR FOR COMBUSTION: The unit heater shall be
installed in a location in which the facilities for
ventilation permit satisfactory combustion of gas,
proper venting, and the maintenance of ambient air
at safe limits under normal conditions of use.
The
unit heater shall be located in such a manner as not to
interfere with proper circulation of air within the confined
space. When buildings are so tight that normal infiltration
does not meet air requirements, outside air shall be
introduced per Sections 1.3.4.2 and 1.3.4.3 of ANSI
Z223.1 for combustion requirements. A permanent
opening or openings having a total free area of not less
than one square inch per 5,000 BTU/Hr (1.5 kW) of
total input rating of all appliances within the space shall
be provided.
NOTICE: Unit Heater sizing should be based on heat
loss calculations where the unit heater output equals
or exceeds heat loss.
