Download 50HJ COBRA Units Guide Specifications, 3 to 12.5 tons (Cooling

HVAC Guide Specifications
Energy Recovery Capability — Constant Volume Application
Size Range:
3 to 121/2 Tons, Nominal (Cooling)
4.4 to 51 kW, Nominal (Accessory Electric Heating)
600 to 3000 cfm of outdoor air
Carrier Model Numbers:
50HJ
Part 1 ― General
1.01 SYSTEM DESCRIPTION
Outdoor rooftop mounted, electrically controlled heating and cooling unit utilizing a hermetic
compressor(s) for cooling duty and accessory electric heat for heating duty. Energy recovery section
is electrically controlled using a rotary compressor for cooling and heating duty. Unit shall discharge
supply air vertically.
1.02 QUALITY ASSURANCE
A. Unit well exceeds ASHRAE 90.1-2001 Energy Standards. Units are Energy Star qualified.
B. Unit shall be rated in accordance with ARI Standards 210/240. Designed in accordance with UL
Standard 1812/1995.
C. Unit shall be designed to conform to ASHRAE 15, latest revision.
D. Unit shall be UL-tested and certified in accordance with ANSI Z21.47 Standards and UL-listed and
certified under Canadian standards as a total package for safety requirements.
E. Roof curb shall be designed to conform to NRCA Standards.
F. Insulation and adhesive shall meet NFPA 90A requirements for flame spread and smoke
generation.
G. Unit casing shall be capable of withstanding 500-hour salt spray exposure per ASTM B117
(scribed specimen).
H. Unit casing shall be capable of withstanding Federal Test Method Standard No. 141 (Method
6061) 5000-hour salt spray.
I. Unit shall be designed in accordance with ISO 9001:2000, and shall be manufactured in a facility
registered to ISO 9001:2000.
J. Each unit shall be subjected to a completely automated run testing on the assembly line. Units
contain a factory-supplied printout indicating tested pressures, amperages, data, and inspectors;
providing certification of the unit status at the time of manufacture.
1.03 DELIVERY, STORAGE, AND HANDLING
Unit shall be stored and handled per manufacturer’s recommendations.
Part 2 ― Products
2.01 EQUIPMENT (STANDARD)
A. General:
Factory assembled, single-piece heating and cooling rooftop unit with energy recovery capability
for vertical discharge applications. Contained within the unit enclosure shall be all factory wiring,
piping, controls, refrigerant charge (R-22), and special features required prior to field start-up.
B. Unit Cabinet:
1. General:
a. Unit cabinet shall be constructed of galvanized steel, and shall be bonderized and coated
with a prepainted baked enamel finish on all externally exposed surfaces.
b. Cabinet panels shall be easily removable for servicing.
c. Holes shall be provided in the base rails for rigging shackles to facilitate maneuvering and
overhead rigging.
d. Unit shall have 2 factory-installed, sloped condensate drain pans made of a non-corrosive
material, providing a common connection with a minimum 3/4-in. drain, and shall comply
with ASHRAE Standard 62. Condensate drain must be installed per manufacturer’s
recommendations.
e. Unit shall have one factory-installed filter access panel to provide filter access with toolless removal.
2. Rooftop Section:
a. Evaporator fan compartment interior cabinet surfaces shall be insulated with a minimum
1/ -in. thick, 1 lb density, flexible fiberglass insulation, neoprene coated on the air side.
2
Aluminum foil-faced fiberglass insulation shall be used in the gas heat compartment.
b. Unit shall have standard thru-the-bottom power connection capability (accessory kit is
required).
3. Energy Recovery Section:
a. All internal panels shall be primer coated.
b. Cabinet interior shall be insulated with a minimum 1/2-in. thick, rigid foam board insulation
with foil facing on the air side.
C. Fans:
1. Evaporator Fan (Rooftop Section):
a. Fan shall be direct or belt driven as shown on the equipment drawings. Belt drive shall
include an adjustable-pitch motor pulley.
b. Fan wheel shall be double-inlet type with forward-curved blades.
c. Bearings shall be sealed, permanently lubricated ball-bearing type for longer life and
lower maintenance.
d. Evaporator fan shall be made from steel with a corrosion-resistant finish and shall be
dynamically balanced.
2. Condenser Fan (Rooftop Section):
a. Fan shall be of the direct-driven (with totally enclosed motors) propeller type and shall
discharge air vertically.
b. Fan shall have aluminum blades riveted to corrosion-resistant steel spiders and shall be
dynamically balanced.
3. Supply Fan and Exhaust Air Fan (Energy Recovery Section):
a. Fans shall be of the double-inlet forward-curved centrifugal type.
b. Fan wheels shall be made from steel with a corrosion-resistant finish and shall be
statically and dynamically balanced.
c. Bearings shall be sealed and permanently lubricated for longer life and lower
maintenance.
D. Compressor(s):
1. Rooftop Section:
a. Fully hermetic type, internally protected scroll-type.
b. Factory mounted on rubber grommets and internally spring mounted for vibration
isolation.
c. On independent circuits (008-014).
2. Energy Recovery Section:
a. Fully hermetic type with electrical overload protection.
b. Factory rubber shock mounted vibration isolation.
E. Coils:
1. Rooftop Section:
a. Standard evaporator and condenser coils shall have aluminum lanced plate fins
mechanically bonded to seamless internally grooved copper tubes with all joints brazed.
b. Dual compressor models (size 008-014) shall have face-split type evaporator coil (circuit
no. 1 on bottom).
2. Energy Recovery Section:
a. Supply and exhaust air coils shall have aluminum plate fins mechanically bonded to
internally enhanced seamless copper tubes with all joints brazed.
b. Tube sheet openings shall be belled to prevent tube wear.
3. Optional Coils:
a. 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 the sheet metal coil pan to minimize
potential for galvanic corrosion between coil and pan. All copper construction shall provide
protection in moderate coastal environments.
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 — 60 deg
of 65 to 90% per ASTM D523-89. Uniform dry film thickness from 0.8 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 minimum 1000 and 250 hours respectively (ASTM D2247-92 and ASTM
D870-92). Corrosion durability shall be confirmed through testing to be no less than 1000
hours salt spray per ASTM B117-90. Coil construction shall be aluminum fins
mechanically bonded to copper tubes.
F. Refrigerant Components:
1. Rooftop section refrigerant circuit components shall include:
a. Fixed orifice metering system (AcutrolTM device).
b. Refrigerant filter drier.
c. Service gage connections on suction, discharge, and liquid lines.
2. Energy recovery section refrigerant circuit components shall include:
a. Fixed orifice metering device combined with maximum overcurrent protection (MOCP)
type thermostatic expansion valve (TXV) to prevent compressor overloading.
b. Service gage connections on suction and discharge lines to charge and evacuate the
system.
c. Ability to route gage hoses through the energy recovery section side panel to eliminate air
bypass during diagnostic periods.
d. Reversing valve.
e. Accumulator located in compressor suction line.
G. Filter Section:
1. Rooftop Section:
a. Standard filter section shall consist of factory-installed, low velocity, throwaway 2-in. thick
fiberglass filters of commercially available sizes.
b. Filter face velocity shall not exceed 320 fpm at nominal airflows.
c. Filter section should use only one size filter.
d. Filters shall be accessible through an access panel with “no-tool” removal.
2. Energy Recovery Section:
a. Standard filter section shall consist of factory-installed low-velocity, throwaway fiberglass
filters of commercially available sizes.
b. Filter face velocity shall not exceed 300 fpm at nominal airflows.
H. Controls and Safeties:
1. Unit Controls:
Unit shall be complete with self-contained low-voltage control circuit protected by a fuse on
the 24-v transformer side (size 008-014 units have a resettable circuit breaker).
2. Safeties:
a. Rooftop Section:
1) Unit shall incorporate a solid-state compressor protector which provides anti-cycle
reset capability at the space thermostat, should any of the following standard safety
devices trip and shut off compressor.
2) Compressor overtemperature, overcurrent.
3) Loss-of-charge/low-pressure switch.
4) Freeze-protection thermostat, evaporator coil.
5) High-pressure switch.
6) Automatic reset motor thermal overload protector.
7) The lockout protection shall be easily disconnected at the control board, if necessary.
b. Energy recovery section shall be provided with the following minimum protections:
1) High-pressure switch.
2) Unit shall incorporate an outdoor coil defrost system to prevent excessive frost
accumulation during heating duty. Defrost system shall be initiated on the basis of
time and coil temperature. A 30/50/90 minute timer shall activate defrost cycle only if
coil temperature is low enough to indicate a heavy frost condition. Defrost cycle shall
terminate when the defrost thermostat is satisfied and shall have a positive
termination time of 10 minutes. A 5-minute time delay shall be built into the defrost
control to prevent compressor short cycling.
I. Operating Characteristics:
1. Rooftop Section:
a. Unit shall be capable of starting and running at 125 F ambient outdoor temperature,
meeting maximum load criteria of ARI Standard 210/240 or 360 at ± 10% voltage.
b. Compressor with standard controls shall be capable of operation down to 25 F ambient
outdoor temperature.
2. Energy Recovery Section:
a. Unit shall be capable of starting and running at 125 F ambient outdoor temperature,
meeting maximum load criteria of ARI Standard 210/240 ± 10% voltage.
b. Compressor with standard controls shall be capable of operation down to 55 F ambient
outdoor temperature in cooling mode and –20 F ambient outdoor temperature in heating
mode.
J. Electrical Requirements:
All unit power wiring shall enter unit cabinet at a single factory-predrilled location.
K. Motors:
1. Rooftop Section:
a. Compressor motors shall be cooled by refrigerant gas passing through motor windings
and shall have line break thermal and current overload protection.
b. Evaporator-fan motor shall have permanently lubricated bearings and inherent automaticreset thermal overload protection. Evaporator motors are designed specifically for Carrier
and do not have conventional horsepower (hp) ratings listed on the motor nameplate.
Motors are designed and qualified in the “air-over” location downstream of the cooling coil
and carry a maximum continuous bhp rating that is the maximum application bhp rating
for the motor; no “safety factors” above that rating may be applied.
c. Totally enclosed condenser-fan motor shall have permanently lubricated bearings, and
inherent automatic-reset thermal overload protection.
2. Energy Recovery Section:
a. Compressor motors shall be cooled by refrigerant gas passing through motor windings
and shall include thermal overload protection.
b. Supply and exhaust-air fan motor shall have permanently lubricated bearings and inherent
automatic reset thermal overload protection.
L. Energy Recovery Section Supply and Exhaust Air Damper:
1. Modulating type supply air damper opens to preset position any time system fans are
energized to provide specified ventilation airflow.
2. Motorized spring return supply air damper automatically closes on loss of power.
3. Capable of providing up to 100% outside air when matched to proper size rooftop unit.
4. Functions as economizer when outdoor air enthalpy sufficient to provide free cooling.
5. Barometric type exhaust air damper with adjustable stops to limit exhaust airflow to specified
cfm. Gravity type damper closes automatically on loss of power or fan shut down.
6. Supply and exhaust rain hoods with cleanable aluminum mesh filters on supply air inlet and
bird screens on exhaust air outlet standard.
M. Special Features:
Certain features are not applicable when the features designated * are specified. For assistance in
amending the specifications, contact your local Carrier Sales Office.
* 1. Carrier PremierLink™ Controls:
a. Shall be available as a factory-installed or as a field-installed accessory.
b. Shall work with CCN and ComfortVIEW™ software.
c. Shall be compatible with ComfortLink™ controllers.
d. Shall be ASHRAE 62-2001 compliant.
e. Shall accept a CO2 sensor in the conditioned space — Demand Control Ventilation
(DCV) Ready.
f. Shall have baud communication rate of 38.4K or faster.
g. Shall be Internet Ready.
h. Shall include an integrated economizer controller.
2. Electronic Programmable Light Commercial Thermidistat Accessory:
The Light Commercial Thermidistat Accessory is a fully programmable thermostat with a
built-in humidistat.
a. Provides direct control of energy recycler control and rooftop unit fans in response to
occupied/unoccupied output signals.
b.
c.
d.
e.
Liquid crystal display (LCD) equipment function indicators display operating mode.
Five-minute compressor delay with override functions.
Keypad lock feature to prevent unauthorized changing of program control.
Holiday Mode — With a single touch of a button mode adjusts all comfort levels for
optimum efficiency while the home is unoccupied and restores the settings to normal
upon return.
f. Comfort and energy savings — Seven-day programming with 4 temperature changes
and humidity set point changes provided per day, means proper ventilation during
occupied periods and savings through reduced energy usage when the building is
unoccupied.
g. Easy to use — Simple instructions are located inside the thermostat’s door.
h. Duplicate Programming — Copy the programmed schedule of one day to the next using
the copy function.
i. Override Capability — Hold function allows the regular schedule to be bypassed with a
temporary setting.
j. Battery-Free — Non-volatile RAM chip requires no battery backup. Retained in memory
so reprogramming is not required after power loss.
3. Humidistat:
Field-installed, wall-mounted humidistat is used to control activation of the dehumidification
package. The humidistat can be set for humidity levels between 20% and 80% relative
humidity.
4. Roof Curbs (Vertical):
a. Full perimeter roof curb with exhaust capability providing separate airstreams for energy
recovery from the exhaust air without supply air contamination.
b. Formed galvanized steel with wood nailer strip and shall be capable of supporting entire
unit weight.
c. Permits installation and securing of ductwork to curb prior to mounting unit on the curb.
d. Sleeper rail shall be available for use with standard unit roof curb.
5. Electric Resistance Heaters and Single Point Kits:
a. Open wire nichrome elements with all necessary safety operating controls.
b. UL listed and indicated on basic unit informative plate.
c. Available in multiples to match heating requirements.
d. Single point kits available for each heater when required.
* 6. Head Pressure Control Package:
Consists of solid-state control and condenser-coil temperature sensor to maintain
condensing temperature between 90 F and 110 F at outdoor ambient temperatures down to
–20 F by condenser-fan speed modulation or condenser-fan cycling and wind baffles.
* 7. Condenser Coil Hail Guard Assembly:
Hail guard shall protect against damage from hail and flying debris.
8. Unit-Mounted, Non-Fused Disconnect Switch:
Shall be factory-installed, internally mounted. NEC and UL approved non-fused switch shall
provide unit power shutoff. Shall be accessible from outside the unit and shall provide
power off lockout capability. (80 amp MAXIMUM)
9. Convenience Outlet:
Shall be factory-installed and internally mounted with easily accessible 115-v female
receptacle. Shall include 15 amp GFI receptacle with independent fuse protection. Voltage
required to operate convenience outlet shall be provided by a factory-installed step-down
transformer. Shall be accessible from outside the unit.
10. High-Static Indoor Fan Motor(s) and Drive(s) (004-012):
High-static motor(s) and drive(s) shall be factory-installed to provide additional performance
range.
11. Condenser Coil Grille:
The grille protects the condenser coil from damage by large objects without increasing unit
clearances.
12. Compressor Cycle Delay:
Unit shall be prevented from restarting for minimum of 5 minutes after shutdown.
13. Thru-the-Bottom Utility Connectors:
14.
15.
16.
17.
18.
19.
Kit shall provide connectors to permit gas and electrical connections to be brought to the
unit through the basepan.
Fan/Filter Status Switch:
Provides status of indoor (evaporator) fan (ON/ OFF) or filter (CLEAN/DIRTY). Status shall
be displayed over communication bus when used with direct digital controls or with an
indicator light at the thermostat.
Outdoor Air Enthalpy Sensor:
The outdoor air enthalpy sensor shall be used to provide single enthalpy control. When
used in conjunction with a return air enthalpy sensor, the unit will provide differential
enthalpy control. The sensor allows the unit to determine if outside air is suitable for free
cooling.
Return Air Enthalpy Sensor:
The return air enthalpy sensor shall be used in conjunction with an outdoor air enthalpy
sensor to provide differential enthalpy control.
Indoor Air Quality (CO2) Sensor:
a. Shall have the ability to provide demand ventilation indoor air quality (IAQ) control.
b. The IAQ sensor shall be available in duct mount, wall mount, and wall mount with LED
display. The set point shall have adjustment capability.
MoistureMi$er™ Dehumidification Package:
The dehumidification package is a factory-installed option that provides increased
dehumidification by further subcooling the hot liquid refrigerant leaving the condenser coil.
The package consists of a subcooling coil located on the leaving airside of the evaporator
coil. The location of this coil in the indoor air stream greatly enhances the latent capacity of
the units.
The package shall be equipped with crankcase heater(s), low pressure switch(es) and
thermostatic expansion valve(s) (TXV). Low pressure switch(es) prevents evaporator coil
freeze-up and TXVs assure a positive superheat condition. If the operation of the
subcooling coil is controlled by a field-installed, wall-mounted humidistat, the
dehumidification circuit will then operate only when needed. Optional field connections for
the humidistat are made in the low voltage compartment of the unit control box.
Hinged Panel Option:
Hinged panel option provides hinged access panels for the filter, compressor, evaporator
fan, and control box areas. Filter hinged panels permit tool-less entry for changing filters.
Each hinged panel is permanently attached to the rooftop unit.