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23
50XP
Packaged Electric Cooling Units
Constant Volume Application
HVAC Guide Specifications
Size Range: 2 to 5 Tons, Nominal Cooling
Carrier Model Number: 50XP
Part 1—General
SYSTEM DESCRIPTION
Outdoor rooftop or ground mounted, electric cooling
unit utilizing a hermetic compressor for cooling duty
and optional electric heating. Unit shall discharge sup-
ply air vertically or horizontally as shown on contract
drawings. Condenser fan/coil section shall have a
draw-thru design with vertical discharge for minimum
sound levels.
QUALITY ASSURANCE
A.Unit shall be rated in accordance with ARI Standards
210/240-94 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 Stan-
dards.
F. Insulation and adhesives shall meet NFPA 90A re-
quirements 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, cooling unit. Con-
tained within the enclosure shall be all factory wiring,
piping, controls, refrigerant charge (R-410A), and spe-
cial features required prior to field start-up.
B. Unit Cabinet:
1. Unit cabinet shall be constructed of phosphated,
zinc-coated, pre-painted steel capable of withstand-
ing 500 hours of salt spray.
2. Normal service shall be through a single removable
cabinet panel.
3. The unit shall be constructed on a rust proof base-
pan that has an externally trapped, integrated sloped
drain pan.
4. Evaporator fan compartment top surface shall be in-
sulated with a minimum 1/2-in. thick, flexible fiber-
glass insulation, coated on the air side and retained
by adhesive and mechanical means. The evaporator
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.
5. Unit shall have a field-supplied condensate trap.
C. Fans:
1. The evaporator fan shall be direct-drive variable
speed motor and control, as shown on equipment
drawings.
2. Fan wheel shall be made from steel, and shall be
double-inlet type with forward curved blades with
corrosion resistant finish. Fan wheel shall be dy-
namically balanced.
3. Condenser fan shall be direct drive propeller type
with aluminum blades riveted to corrosion resistant
steel spiders, be dynamically balanced, and dis-
charge air vertically.
D. Compressor:
1. Fully hermetic compressors with factory-installed
vibration isolation.
2. Scroll compressors shall be standard on all units.
E. Coils:
Evaporator and condenser 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 TXV type.
G. Filters:
Filter section shall consist of field-installed, throw-
away, 1-in. thick fiberglass filters of commercially
available sizes.
H. Controls and Safeties:
1. Unit controls shall be complete with a self-con-
tained low voltage control circuit.
2. Units shall incorporate an internal compressor pro-
tector that provides reset capability.
3. Unit shall provide High and Low/Loss-of-Charge
Pressure Safety Protection.
I. Operating Characteristics:
1. Unit shall be capable of starting and running at
125°F ambient outdoor temperature, exceeding
maximum load criteria of ARI Standard 210.
2. Compressor with standard controls shall be capable of
operation down to 55° F ambient outdoor temperature.
3. Indoor Fan on/off delay profile is selected (for cool-
ing) on the Easy Select™ Board.
J. Electrical Requirements:
All unit power wiring shall enter the unit cabinet at a
single location.
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.
Guide specifications