HVAC GUIDE SPECIFICATIONS — SECTION 15678
SPLIT-SYSTEM HEAT PUMP OUTDOOR UNIT
SIZE RANGE:
172,000 BTUH HEATING
15 NOMINAL TONS COOLING
BRYANT MODEL NUMBER:
541A180
PART 2 — GENERAL
1.01 SYSTEM DESCRIPTION
A. Outdoor-mounted, electrically controlled, air-cooled split system heat pump unit utilizing a semi-hermetic reciprocating-type compressor for refrigerant compression. Unit shall function as the outdoor component of an air-to-air electric heat pump system.
B. Unit can be used in a refrigerant circuit to match Packaged Air-Handling Unit(s), Section 15859, for matched systems approved by manufacturer.
1.02 QUALITY ASSURANCE
A. Unit performance shall be certified in accordance with ARI Standards 340/360.
B. The refrigerant coil shall be designed and tested in accordance with ASHRAE 15 Safety Code for Mechanical Refrigeration.
C. Unit shall be constructed in accordance with ETL and ETL, Canada, regulations and shall carry the ETL and ETL, Canada, labels of approval.
D. Coil leak testing shall be at 350 psig air pressure with the coil submerged in water. After testing, the coil shall be dehydrated and charged with dry air.
E. Unit shall be manufactured in a facility registered to the ISO 9001:2000 manufacturing quality standard.
F. Unit casing shall be capable of withstanding 500-hour salt spray exposure per ASTM B117 (scribed specimen).
1.03 DELIVERY, STORAGE, AND HANDLING
Unit shall be stored and handled in accordance with unit manufacturer’s instructions.
PART 2 — PRODUCTS
2.01 EQUIPMENT
A. General:
Outdoor-mounted, air-cooled split system heat pump unit shall be suitable for on-the-ground or rooftop installation on a full level pad or on raised pads at each support point. The unit shall consist of a semi-hermetic reciprocating refrigerant compressor/motor assembly, a fin-tube coil, propeller-type fans, fan motors, refrigerant controls, and a control box. All components shall be factory assembled as a single unit. A holding charge of R-22 shall be included.
B. Unit Cabinet:
1. Cabinet shall be constructed of galvanized steel, bonderized, and finished with baked enamel.
2. Fan venturi housings and guards shall be assembled on the unit.
3. A removable panel or hinged door shall be provided for access to the compressor and control compartments.
4. A refrigerant accumulator with a fusible plug relief shall be installed in the cabinet.
C. Fans:
1. Propeller fans shall be directly driven by weather-proof motors. Fan motor bearings shall be permanently lubricated. The lead fan motor shall be suitable for application with accessory head pressure control.
2. Fans shall be arranged for vertical upblast discharge.
D. Compressor/Motor Assembly:
1. Semi-hermetic, reciprocating-type compressor shall be complete with a motor and oil pump all on a single polished crankshaft.
2. Motor stator winding shall be NEMA Class F rated, suitable for operation in a refrigerant atmosphere.
3. Oil pump shall be automatically reversible.
4. Casing shall include suction and discharge shutoff valves, capacity control device, oil level control orifice, oil-pressure regulating valve, and a crankcase oil heater.
5. Suction and discharge valves shall be Swedish steel, reed-type flapper valves.
6. Pistons and connecting rods shall be high-density aluminum alloy castings. Pistons shall be equipped with automotive-type compression and oil scraper rings.
7. Pump-end bearing shall be cast aluminum. Motor-end bearing shall be steel-backed, tin-base babbit type.
8. Compressor assembly shall be installed on spring vibration isolators.
E. Coil:
Coil shall have copper tubes, aluminum plate fins (copper fins optional), and galvanized steel tube sheets. The fins shall be bonded to tubes by mechanical expansion. Coil shall be circuited for subcooling during Cooling mode operation.
F. Controls and Safeties:
Operating controls and safeties shall be factory selected, assembled, and tested. Minimum control functions shall be as listed below:
1. Controls:
a. Capacity control valves on the compressor shall be self-contained, electrically actuated, and suction cutoff.
b. Head pressure control shall be achieved by fan cycling: One fan shall be cycled in response to liquid pressure, and one fan shall be non-cycling. Both fans shall be activated in the Heating mode.
c. Defrost control shall consist of a time and temperature activated system that initiates defrost periodically in response to a temperature signal.
2. Safeties:
a. Low oil pressure switch cutout.
b. High discharge pressure cutout.
c. Loss-of-charge cutout.
d. Compressor motor current and temperature overload cutouts.
e. Liquid line solenoid valve.
f. Filter drier in the Heating mode.
g. Device to hold the compressor off-line until reset manually when any of the following listed cutouts are tripped: High discharge pressure, high temperature, and loss-of-charge.
h. Compressor short-cycle protection control to prevent compressor restart after shutdown until a timed period has expired.
G. Electrical Requirements:
1. Factory supplied and installed transformer shall provide 24 v control voltage.
2. All power and control circuit wiring shall comply with local and national codes.
H. Special Features:
1. Low-Ambient Temperature Control:
A low-ambient temperature control shall be available as a field-installed accessory. This low-ambient control shall regulate speed of the condenser-fan motor in response to the saturated condensing temperature of the unit. The control shall maintain correct condensing pressure at outdoor temperatures down to –20 F.
2. Mounting Legs:
Legs shall hold the unit approximately 18 in. off the ground to allow space for drainage.
3. Outdoor Coil Grille:
Protects outdoor coil from large objects and vandalism.
4. Optional Outdoor Coil Materials:
a. Pre-Coated Aluminum-Fin Coils:
Shall have a durable epoxy-phenolic coating to provide protection in mildly corrosive coastal environments. Coating shall be applied to the aluminum fin stock prior to the fin stamping process to create an inert barrier between the aluminum fin and copper tube. Epoxy-phenolic barrier shall minimize galvanic action between dissimilar metals.
b. E-Coated Aluminum-Fin Coils:
Shall have a flexible epoxy polymer coating uniformly applied to all coil surface areas without material bridging between fins. Coating process shall ensure complete coil encapsulation. Color shall be high-gloss black with gloss requirements of 60° of 65 to 90% per ASTM D523-89. Uniform dry film thickness from 0.8 mil to 1.2 mil on all surface areas including fin edges. Superior hardness characteristics of 2H per ASTM D3363-92A and cross-hatch adhesion of 4B-5B, per ASTM D3359-93. Impact resistance shall be up to 160 in./lb (ASTM D2794-93). Humidity and water immersion resistance shall be up to a minimum of 1000 and 250 hours respectively (ASTM D2247-92 and ASTM D870-92). Corrosion durability shall be confirmed through testing to no less than 1000 hours salt spray per ASTM B117-90. Coil construction shall be aluminum fins mechanically bonded to copper tubes.
5. Thermostat Controls:
a. Programmable multi-stage thermostat with 7-day clock, holiday scheduling, large backlit display, remote sensor capability, and Title 24 compliance.
b. Commercial electronic thermostat with 7-day timeclock, auto-changeover, multistage capability, and large LCD temperature display.
c. Non-programmable thermostat with one or 2-stage cooling. Available with or without tamperproof switches and automatic changeover.