standard. For areas where the temperature will be
below 2 degrees C 35 degrees F and year round
operation of the unit is essential, special
accessories will have to be specified for operation
below 2 degrees C 35 degrees F.
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Completely self-contained, slide-in assembly or removable chassis with
welded, hermetically sealed, air-cooled refrigeration system, outdoor fan,
indoor fan, control box, and ventilation damper. Provide refrigeration
sections capable of installation or removal without the use of tools.
Refrigeration sections shall include refrigeration circuit tubing, wiring,
and safety controls, and shall operate down to 2 degrees C 35 degrees F
outdoor temperature and 21 degrees C 70 degrees F indoor temperature,
without compressor short cycling while delivering not less than 100 percent
of rated cooling capacity. Units shall have drains to the building
exterior to eliminate excess driving rain. Condensate shall not drain onto
building exterior or interior.
a.
Hermetic type with vibration isolation devices.
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NOTE: Research project location conditions to
determine the environmental effects on finned tube
coils. The research should include a survey of
existing similar equipment. If needed, rewrite the
specifications based on the conclusions of the
research. Consideration should be given to the
following combinations based on past experience of
these materials in dealing with the local conditions.
1.
Copper tube and aluminum fins, coated;
2.
Copper tube and copper fins, coated;
3.
Aluminum tube and aluminum fins, coated;
4.
Aluminum tube and aluminum fins, uncoated;
5.
Copper tube and copper fins, uncoated; and
6. Copper tube and aluminum fins, uncoated.
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b.
Coils: Constructed of seamless copper or aluminum tubing with
copper or aluminum fins bonded to tubes. [Coat outdoor air coils
with factory applied corrosion resistant treatment. Coils to be
coated shall be part of manufacturer's standard product for
capacities and ratings indicated and specified. Provide plate
type fins.]
c.
Outdoor Fans: Direct connected centrifugal type with aluminum or
plastic wheel and forward curved blades or direct connected
aluminum propeller type. Design fans so that condensate will
evaporate without drip, splash, or spray on building exterior.
d.
Indoor Fans: Direct connected centrifugal type with aluminum,
galvanized steel, or plastic wheel and forward curved blades.
Provide minimum two-speed motor with built-in overload protection.
SECTION 15730N
Page 14
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