Sterling MS User Manual
Page 4

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LOCATION
Before placing the Make-Up Air unit in its permanent
location, make certain that the structure is capable of
carrying the additional load of this equipment. Check the
unit weight given at the end of this manual.
Refer to unit data plate for required clearances to combustible
material, and Figure 11 for manufacturer’s recommendations.
Do not place unit in a location where
service personnel can not safely service this
equipment or personal injury could result.
NOTICE: When selecting a location for these Make-
Up Air Units, both the size of the unit and the heating
requirements of the building must be considered.
NOTICE: The furnace section(s) of this unit is equipped
for bottom access serviceability only! Provide
adequate clearance (base rail to fl oor is 18 inches
minimum).
COMBUSTION AIR CONSIDERATIONS
The presence of chlorine vapors or other corrosive vapors in the
combustion air supply for gas-fi red heating equipment presents
a potential corrosive hazard. Chlorine will, when exposed
to fl ame, precipitate from the compound (usually freon or
degreaser vapors) and go into solution with any condensation
that is present in the heat exchanger or associated parts. The
result is hydrochloric acid which will readily attack all metals,
including 300 grade stainless steel. Care should be taken
to separate these vapors from the combustion process.
LOCATIONS TO AVOID
Unit heaters should not be installed within corrosive or
fl ammable atmospheres. Do not locate any gas fi red
heater where air for combustion contains chlorinated
vapors or acid fumes.
Presence of these air impurities can
cause premature failure of the heat exchanger and
void the warranty (See limited warranty on page 30).
The venting system must be installed in accordance with
heater manufacturer’s instructions. The venting system is
an integral part of the unit and must not be altered in
the fi eld!
MOUNTING HEIGHT
1. When a Gas Fired Make-Up Air Handler is discharging
directly into the heated space, a mounting height of
eight feet (2.4m) above the fl oor is recommended.
Less effi cient air distribution results at higher levels.
2. When Gas Fired Indoor Make-Up Air Handlers are
installed in airplane hangars, NFPA specifi es that the
units must be at least ten feet (3.0m) above the upper
surface of wings or engine enclosures of the highest
aircraft to be stored in the hangar. This measurement
should be made from the wing or engine enclosure
(whichever is higher from the fl oor) to the bottom of
the heater. Heaters must be installed at least eight
feet (2.4m) above the fl oor in shops, offi ces, and other
sections of the hangar where aircraft are not stored
or housed. Refer to NFPA 409 Aircraft Hangars.
3. In parking structures, Gas Fired Indoor Make-Up Air
Handlers must be installed so that the burner fl ames
are located 18" (457mm) above the fl oor or protected
by a partition not less than 18" (457mm) high as
specifi ed in NFPA 88A Parking Structures.
4. In public repair garages, Gas Fired Make-Up Air
Handlers must be installed in a detached building
or room separated from repair areas as specifi ed in
NFPA 88B Repair Garages.