Split-System Heat Pump Outdoor Unit
HVAC Guide Specifications — Section 15678
Size Range:
83,000 Nominal Btuh Heating
7 1 /2 Nominal Tons Cooling
Carrier Model Number: 38AQS008
Part 1 — General
1.01 SYSTEM DESCRIPTION
A. TOutdoor-mounted, electrically controlled, air-cooled split system heat pump unit utilizing
a reciprocating-type semi-hermetic compressor for refrigerant compression. Unit shall
function as the outdoor component of an air-to-air electric heat pump system.
B. Unit shall be used in a refrigerant circuit to match Packaged Air-Handling Unit, Section
15859, for matched system approved by manufacturer.
1.02 QUALITY ASSURANCE
A. Unit performance shall be certified in accordance with ARI Standards 210/240 and 270,
latest versions.
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 UL and UL, Canada regulations and shall
carry the UL and UL, Canada labels of approval. Units shall be manufactured in a facility
registered to the ISO 9001 manufacturing quality standard.
D. Coil leak testing shall be at 300 psig air pressure with the coil submerged in water. After
testing, the coil shall be dehydrated and charged with dry air.
E. 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-theground 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 compressor, a fin-tube coil,
propeller-type fan, fan motor, refrigeration control devices, and a control box. All
components shall be factory assembled as a single unit. A holding charge of R-22 shall
be included. Units shall be used in a refrigeration circuit matched with a 40RMQ008
packaged air-handling unit.
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 shall be provided for access to compressor and control
compartments.
4. A refrigerant accumulator with a fusible plug relief shall be installed in the cabinet.
5. Lifting holes shall be provided to facilitate rigging.
C. Fan:
1. Propeller fan shall be directly driven by weather-proof motors. Fan motor bearings
shall be permanently lubricated.
2. Fan shall be arranged for vertical discharge.
D. Compressor/Motor Assembly:
1. Semi-hermetic, reciprocating-type 06D 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 discharge shutoff valves, oil level control orifice, oil-pressure
regulating valve, and a crankcase oil heater.
E.
F.
G.
H.
5. Suction and discharge manifold 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.
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 in cooling mode operation. For refrigerant control, the unit
shall be equipped with a liquid line, suction line, and compressor discharge service
valves. The unit shall include an accumulator with a fusible plug relief and a reversing
valve for effective heat pump operation. Each unit system shall have 3 service ports: one
on the suction line, one on the liquid line, and one on the compressor discharge line.
Each port shall be capped for leak tightness.
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. Time-delay restart control to prevent compressor short-cycling.
b. Defrost control to consist of a time and temperature activated system that
initiates defrost mode at selectable intervals of 30, 50, or 90 minutes in response
to a temperature signal.
2. Safeties:
a. High discharge pressure cutout switch.
b. Loss-of-charge cutout switch.
c. Compressor motor current and temperature overload cutouts.
d. Five-minute recycle protection to prevent compressor short cycling.
e. Device to hold the compressor off-line until manual reset at the thermostat when
any of the following are tripped: High discharge pressure, high compressor motor
temperature, or loss of charge.
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.
Special Features:
1. Head Pressure Control:
Control shall vary the fan motor speed in response to the saturated condensing
temperature of the unit. The control shall be capable of maintaining a condensing
temperature of 100 F ± 10 F with outdoor temperature at –20 F.
2. Outdoor Thermostat:
Adjustable control shall activate electric heaters in stages to provide supplemental
heat. Range: –30 F to 90 F.
3. Gage Panel:
Panel shall provide one suction pressure and one discharge pressure gage mounted
on a common panel. A shut-off valve shall be provided for each gage.
4. Coil Guard:
Grille shall protect outdoor coil from damage by large objects or vandalism.
5. Hail Guard:
Guard shall protect unit against damage from damage by hail or flying debris.
6. 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. Copper-Fin Coils:
Shall be constructed of copper fins mechanically bonded to copper tubes and
copper tube sheets. Galvanized steel tube sheets shall not be acceptable. A
polymer strip shall prevent coil assembly from contacting sheet metal coil pan to
minimize potential for galvanic corrosion between the coil and pan. All copper
construction shall provide protection in moderate coastal applications.
c. Post-Coated Aluminum-Fin Coils:
Shall have a durable organic coating uniformly applied over all coil surfaces.
Coating shall be deep brown color applied by a dip and bake process to ensure
complete encapsulation of all coil surfaces. Coated coil shall withstand 1,000hour salt spray test in accordance with ASTM B117. Coil construction shall be
aluminum fins mechanically bonded to copper tubes.
d. Post-Coated Copper-Fin Coils:
Shall have a durable organic coating uniformly applied over all coil surfaces.
Coating shall be deep brown color applied by a dip and bake process to ensure
complete encapsulation of all coil surfaces. Coated coil shall withstand 1,000
hour-salt spray test in accordance with ASTM B117. Coil construction shall be
copper fins mechanically bonded to copper tubes.
7. Thermostat Controls:
a. Programmable multi-stage thermostat with 7-day clock, holiday scheduling, large
backlit display, remote sensor capability, and Title 24 compliance.
b. TEMP System programmable communicating multi-stage thermostat with fan
switch, timeclock, LCD display, °F/°C capability, and CCN (Carrier Comfort
Network) compatibility.
c. Commercial Electronic Thermostat with 7-day timeclock, auto-changeover, multistage capability, and large LCD temperature display.
d. Non-programmable thermostat with fan switch subbase.