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GUIDE SPECIFICATIONS
Packaged Heat Pumps
Constant Volume Application
HVAC Guide Specifications
Size Range: 2to5Tons,NominalCooling
Carrier Model Number: 50SZ
Part 1⎯General
SYSTEM DESCRIPTION
Outdoor, packaged, air-- to -- air heat pump unit utilizing a
hermetic scroll compressor for cooling duty and optional
electric heating. Unit shall discharge supply air vertically or
horizontally as shown on contract drawings. Outdoor fan/coil
sectionshallhavea draw--thrudesign with vertical dischargefor
minimum sound levels.
QUALITY ASSURANCE
A. Unit shall be rated in accordance with ARI Standards
210/240-- 03 and 270--95.
B. Unit shall be designed in accordance with UL Standard
1995.
C. Unit shall be manufactured in a facility registered to ISO 9001
manufacturing quality standard.
D. Unit shall be UL listed and c--UL certified as a total package for
safety requirements.
E. Roof curb shall be designed to conform to NRCA Standards.
F. Insulation and adhesives shall meet NFPA 90A requirements
for flame spread and smoke generation.
G. Cabinet insulation shall meet ASHRAE Standard 62P.
DELIVERY, STORAGE AND HANDLING
Unit shall be stored and handled per manufacturer’s
recommendations.
Part 2 ⎯ Products
EQUIPMENT
A. General:
Factory--assembled, single--piece, heat pump unit. Contained
within the enclosure shall be all factorywiring, piping, controls,
refrigerant charge (R-- 22), and special features required prior to
field start--up.
B. Unit Cabinet:
9. Unit cabinet shall be constructed of phosphated,
zinc--coated, pre--painted steel capable of withstanding 500
hours of salt spray.
10. Normal service shall be through a single removable cabinet
panel.
11. The unitshallbeconstructed on a rustproof unitbase thathas
an externally trapped, integrated sloped drain.
12. Indoor fan compartment top surface shall be insulated with
a minimum 1/2--in. thick, flexible fiberglass insulation,
coated on the air side and retained by adhesive and
mechanical means. The indoor wall sections will be
insulated with a minimum semi--rigid, foil--faced board
capable of being wiped clean. Aluminum foil--faced
fiberglass insulation shall be used in the entire indoor air
cavity section.
13. Unit shall have a field--supplied condensate trap.
14. Metal Insulated Duct Covers for side discharge will be
standard on all sizes.
15. Unit insulation conforms to ASHRAE 62P.
C. Fans:
1. The indoor fan shall be 3--speed, d irect--drive, as shown on
equipment drawings.
2. Fan wheel shallbe made from steel and shallbe double-- inlet
type with forward--curved blades with corrosion resistant
finish. Fan wheel shall be dynamically balanced.
3. Outdoor fan shall be direct-- drive, propeller--type with
aluminum blades riveted to corrosion resistant steel spiders,
be dynamically balanced, and discharge air vertically.
D. Compressor:
1. Fully hermetic compressors with factory--installed vibration
isolation.
2. Scroll compressors shall be standard on all units.
3. Compressor Protection:
Defrost control shall protect compressor by preventing
“short cycling.”
E. Coils:
Indoor and outdoor coils shall have aluminum plate fins
mechanically bonded to seamless copper tubes with all joints
brazed. (Copper/copper and vinyl--coated construction
available as option.) Tube sheet openings shall be belled to
prevent tube wear .
F. Refrigerant Metering Device:
Refrigerant metering device shall be of the fixed orifice feed
type.
G. Filters:
Filter section shall consist of field--installed, throwaway, 1--in.--
thick fiberglass filters of commercially available sizes.
H. Controls and Safeties:
1. Unit controls shall be complete with a self--contained, low--
voltage control circuit.
2. Units shall incorporate an internal compressor protector that
provides reset capability.
I. Operating Characteristics:
1. Unit shall be capable of starting and running at 125_F
(51.6_C) ambient outdoor temperature per maximum load
criteria of ARI Standard 240 --94.
2. Compressor with standard controls shall be capable of
operation down to 40_F(4.4_C) ambient outdoor
temperature in cooling mode.
3. Unit shall be provided with 30--second fan time delay after
the thermostat is satisfied.
J. Electrical Requirements:
Allunitpower wiringshall enterthe unitcabinet ata singleloca-
tion.
K. Motors:
1. Compressor motors shall be of the refrigerant--cooled type
with line-- break thermal and current overload protection.
2. All fan motors shall have permanently lubricated bearings,
and inherent, automatic reset, thermal overload protection.
3. Condenser fan motor shall be totally enclosed.
L. Special Features Available:
1. Louvered Grille:
Wire grille shall be standard on all units. Louvered grille
shallbeavailable asafactory--installed option to providehail
guard and vandalism protection.
50SZ
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