Specs

24
GUIDE SPECIFICATIONS
SMALL PACKAGED PRODUCT AIR--TO--AIR
HEAT PUMP CONSTANT VOLUME APPLICATION
HVAC GUIDE SPECIFICATIONS
SIZE RANGE: 2 TO 5 TONS, NOMINAL (COOLING)
PART I -- GENERAL
SYSTEM DESCRIPTION
Outdoor packaged, electrically controlled, air--to--air heat
pump utilizing a scroll compressor for heating and cooling
duty. Unit shall discharge supply air horizontally as shown on
contract drawings.
QUALITY ASSURANCE
A. Unit shall be rated in accordance with AHRI Standards
210/240, and 270. Designed in accordance with UL
Standard 1995.
B. Unit shall be designed to conform to ASHRAE 15.
C. Unit shall be UL listed as a total package for safety
requirements.
D. Insulation and adhesive shall meet NFPA 90A
requirements for flame spread and smoke generation.
DELIVERY, STORAGE, AND HANDLING
Unit shall be stored and handled per manufacturer’s
recommendations.
PART 2-- PRODUCTS
EQUIPMENT
A. General:
Factory--assembled, single piece, air--to--air heat pump.
Contained within the unit enclosure shall be all factory wiring,
piping, controls, and refrigerant charge (R--410A).
B. Unit Cabinet:
1. Unit cabinet shall be constructed of phosphated,
bonderized, zinc--coated, prepainted steel.
2. Basepan shall be made of a single--piece non--corrosive,
composite material.
3. Indoor fan compartment cabinet surfaces shall be insulated
with a minimum 1/2 in. (12.7 mm) thick, flexible
insulation, coated on the air side, with aluminum foil--faced
insulation.
4. Cabinet panels shall be easily removable for servicing.
5. Unit shall have a factory--installed, sloped, noncorrosive,
condensate drain.
6. Unit insulation conforms to ASHRAE 62P.
C. Fans:
1. Indoor Blower (Indoor Fan):
a. Fan shall be multispeed, direct drive as shown on the
equipment drawings.
b. 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.
2. 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 shall
discharge air upwards.
D. Compressor:
Fully--hermetic scroll type with external vibration isolation.
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.
3. Outdoor coil shall be protected by metal louvered panels.
F. Refrigerant Components:
1. TXV and AccuRater feed system.
2. Service gauge connections on suction and discharge lines.
3. Equipped with liquid line filter drier.
4. Equipped with accumulators on all sizes.
G. Controls and Safeties:
1. Unit Controls:
a. Unit shall be complete with self--contained low voltage
control circuit.
b. Unit shall incorporate an outdoor coil defrost system to
prevent excessive frost accumulation during heating
cycle and shall be controlled as follows:
(1.) Defrost shall be initiated on the basis of time and
coil temperature.
(2.) A 30/60/90--minute timer shall activate defrost
cycle only if coil temperature is low enough to
indicate a heavy frost condition.
(3.) Defrost cycle shall terminate when defrost
thermostat is satisfied or shall have a positive
termination time of 10 minutes.
2. Safeties:
a. High Pressure Switch
b. Loss of Charge Switch
H. Operating Characteristics:
1. Unit shall be capable of starting and running at 125F
(51.7C) ambient outdoor temperature (60 size max ambi-
ent is 115F [46.1C]).
2. Compressor with standard controls shall be capable of
operation down to 40F(4.4C) ambient outdoor
temperature in cooling duty.
3. Compressor shall be capable of operation in heating cycle
down to --20F (--28.9C) ambient outdoor--air temperature.
4. Unit shall be capable of simultaneous heating duty and
defrost cycle operation when using electric heaters indicated
in Section L, Special Features.
I. Electrical Requirements:
All unit power wiring shall enter unit cabinet at a single
location.
J. 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.
PH4Z