23
GUIDE SPECIFICATIONS
SINGLE--PACKAGED ELECTRIC COOLING UNITS
CONSTANT VOLUME APPLICATION
HVAC GUIDE SPECIFICATIONS
SIZE RANGE:
2 TO 5 TONS, NOMINAL COOLING
MODEL NUMBER: 50XL
PART I -- GENERAL
SYSTEM DESCRIPTION
Outdoor rooftop or ground mounted electric cooling unit utiliz-
ing a 2 stage hermetic compressor for cooling duty and optional
electric heating. Unit shall discharge supply air vertically or hori-
zontally as shown on contract drawings. Outdoor fan/coil section
shall have a draw--thru design with vertical discharge for mini-
mum sound levels.
QUALITY ASSURANCE
A. Unit shall be rated in accordance with ARI Standards
210/240, and 270.
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 recommen-
dations.
PART 2-- PRODUCTS
EQUIPMENT
A. General:
Factory--assembled, single--piece, cooling unit. Contained with-
in the unit enclosure shall be all factory wiring, piping, controls,
refrigerant charge (R--410A), and special features required prior
to field start--up.
B. Unit Cabinet:
1. Unit cabinet shall be constructed of phosphated, zinc--coated,
prepainted steel capable of withstanding 500 hrs of salt spray.
2. Normal service shall be through a single removable cabinet
panel.
3. The unit shall be constructed on a rust proof unit base that has
an externally trapped, integrated sloped drain pan.
4. Indoor fan compartment top surface shall be insulated with a
minimum 1/2--in. (13 mm)
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 foil--faced insulation capable of being wiped clean.
Aluminum foil--faced fiberglass insulation shall be used in the
entire indoor air cavity seciton.
5. Unit shall have a field--supplied condensate trap.
C. Fans:
1. The indoor fan shall be variable--speed motor and control, as
shown on equipment drawings.
2. Fan wheel shall be made from steel, be double--inlet type. It
shall have forward--curved blades with a corrosion--resistant
finish and shall be dynamically balanced.
3. Outdoor fan shall be of the direct--driven propeller type with
aluminum blades, riveted to corrosion--resistant steel spiders.
It shall be dynamically balanced and discharge air vertically.
D. Compressor:
1. Fully hermetic 2 stage compressors with factory--installed
vibration isolation.
2. Two stage scroll compressors shall be standard on all units.
E. Coils:
1. Indoor and outdoor coils shall have aluminum plate fins
mechanically bonded to seamless copper tubes with all joints
brazed.
2. Tube sheet openings shall be bellied 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 self--contained low
voltage control circuit.
2. Units shall incorporate an internal compressor protector 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
(51.6
°
C) 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 (12.7
°
C) ambient outdoor
temperature.
3. Unit shall be capable of low--ambient cooling (below 55
_
F
(12.7
°
C) ambient outdoor temperature) with low--ambient
cooling enabled on the UI.
J. Electrical Requirements:
All unit power wiring shall enter 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. Outdoor fan motor shall be totally enclosed.
L. Grille
1. Louvered Grille:
Louvered grille shall be standard on all units.
50X
L
