Carrier 48EJ, 48EW, 48EY024-068, 48AW, 48AY020-060, 48EK, 48AK, 48AJ specifications Protective Devices

Page 95

Filter Drier — Replace whenever refrigerant system is ex- posed to atmosphere.

Protective Devices

COMPRESSOR PROTECTION

Overcurrent — Each compressor has one manual reset, cali- brated trip, magnetic circuit breaker. Do not bypass connec- tions or increase the size of the circuit breaker to correct trou- ble. Determine the cause and correct it before resetting the breaker.

Overtemperature — Each 06D type compressor (48AJ,AK, AW,AY020-035 and 48EJ,EK,EW,EY024-038 units only) has an internal protector to protect it against excessively high dis- charge gas temperatures.

Crankcase Heater — Each compressor has a crankcase heater to prevent absorption of liquid refrigerant by oil in the crank- case when the compressor is idle. Since power for the crank- case heaters is drawn from the unit incoming power, main unit power must be on for the heaters to be energized.

IMPORTANT: After a prolonged shutdown or service job, energize the crankcase heaters for 24 hours before starting the compressors.

EVAPORATOR FAN MOTOR PROTECTION — A manu- al reset, calibrated trip, magnetic circuit breaker protects against overcurrent. Do not bypass connections or increase the size of the breaker to correct trouble. Determine the cause and correct it before resetting the breaker. If the evaporator-fan motor is replaced with a different horsepower motor, resizing of the circuit breaker is required. Contact Carrier Application Engineering.

CONDENSER-FAN MOTOR PROTECTION — Each condenser-fan motor is internally protected against overtemperature.

HIGH- AND LOW-PRESSURE SWITCHES — If either switch trips, or if the compressor overtemperature switch activates, that refrigerant circuit will be automatically locked out. See Compressor Lockout Logic section on this page.

FREEZE PROTECTION THERMOSTAT (FPT) — Freeze protection thermostats are located on the evaporator coil for each circuit. One is located at the top and bottom of each coil. It detects frost build-up and turns off the compressor, allowing the coil to clear. Once the frost has melted, the compressor can be reenergized.

Relief Devices — All units have relief devices to protect against damage from excessive pressures (i.e., fire). These de- vices are installed on the suction line, liquid line, and on the compressor.

Power Circuit — A typical power wiring schematic is shown in Fig. 77.

Control Circuit, 24-VThis control circuit is protect- ed against overcurrent by a 3.2 amp circuit breaker (CB4). Breaker can be reset. If it trips, determine cause of trouble be- fore resetting. A typical 24-v control wiring schematic is shown in Fig. 78 and 79.

Control Circuit, 115-VThis control circuit is pro- tected against overcurrent by a 5.2 amp circuit breaker (CB3). Breaker can be reset. If it trips, determine cause of trouble be- fore resetting. A typical 115-v control wiring schematic is shown in Fig. 80 and 81.

Compressor Lockout Logic — If any of the safeties trip, the circuit will automatically reset (providing the safety has reset) and restart the compressor in 15 minutes. If any of the safeties trip 3 times within a 90-minute period, then the cir- cuit will be locked out and will require manual resetting by turning off either the unit disconnect or the control circuit breaker, or opening the thermostat.

If the compressors have bee off for more than 15 minutes and the outdoor-air temperature (OAT) is less than 45 F then safeties will be ignored for 5 minutes.

Replacement Parts — A complete list of replacement parts may be obtained from any Carrier distributor upon request.

LEGEND for Fig. 77-83 — Typical Wiring Schematics

 

 

 

LEGEND

AFS

Airflow Switch

HTSASP — Heating Supply Air Set Point

AHA

Adjustable Heat Anticipator

 

Potentiometer

BP

Building Pressure

HV

High Voltage

BR

Burner Relay

IDM

Induced-Draft Motor

C

Contactor, Compressor

IFC

Indoor Fan Contactor

CAP

Capacitor

IFCB

Indoor Fan Circuit Breaker

CB

Circuit Breaker

IFM

Indoor-Fan Motor

CC

Cooling Compensator

IFR

Indoor-Fan Relay

CCB

Controller Circuit Breaker

IGC

Integrated Gas Unit Controller

CCH

Crankcase Heater

IP

Internal Protector

CLSASP — Cooling Supply Air

L

Light

 

Set Point Potentiometer

LPS

Low-Pressure Switch

COM

Communication

LS

Limit Switch

COMP

Compressor Motor

MGV

Main Gas Valve

CR

Control Relay

NC

Normally Closed

CV

Constant Volume

NO

Normally Open

DM

Damper Motor

OAT

Outdoor-Air Thermostat

DP

Duct Pressure

OD

Outdoor

EC

Enthalpy Control

OFC

Outdoor-Fan Contactor

FLA

Full Load Amps

OFM

Outdoor-Fan Motor

FPT

Freeze Protection Thermostat

PEC

Power Exhaust Contactor

FU

Fuse

PEM

Power Exhaust Motor

GVR

Gas Valve Relay

PES

Power Exhaust Sequencer

HPS

High-Pressure Switch

PESC

Power Exhaust Sequencer Controller

HS

Hall Effect Sensor

PL

Plug Assembly

RAT

Return-Air Thermistor

RS

Rollout Switch

SAT

Supply-Air Thermostat

SEN

Sensor

SW

Switch

TB

Terminal Block

TC

Thermostat, Cooling

TH

Thermostat, Heating

TRAN — Transformer

UL

Compressor Unloader

VFD

Variable Frequency Drive

Terminal (Marked)

Terminal (Unmarked)

Terminal Block

Splice

Factory Wiring

Field Wiring

To indicate common potential only. Not to represent wiring.

95

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Contents Installation, Start-Up Service Instructions Instructions on Make Unit Duct ConnectionsRoof Curb 48AJ,AK020-030 and 48EJ,EK024-034 Units Roof Curb 48AJ,AK034-050 and 48EJ,EK038-048 Units Roof Curb 48AJ,AK060 and 48EJ,EK054-068 Units Page Base Unit Dimensions 48AJ,AK020-030 Base Unit Dimensions 48AJ,AK035-050 Base Unit Dimensions 48AJ,AK060 Base Unit Dimensions 48AW,AY020-030 Base Unit Dimensions 48AW,AY035-050 Base Unit Dimensions 48W,AY060 Base Unit Dimensions 48EJ,EK024-034 Base Unit Dimensions 48EJ,EK038-048 Base Unit Dimensions 48EJ,EK054-068 Base Unit Dimensions 48EW,EY024-034 Base Unit Dimensions 48EW,EY038-048 Base Unit Dimensions 48EW,EY054-068 AT Each Corner % 48EJ,EW,EK,EYD030 Rigging Weights 48AJ,AK,AW,AY UnitsAT Each Corner % 48EJ,EW,EK,EYD024 48EJ,EW,EK,EYD028Unit 48AJ,AK,AW,AY Physical Data 48AJ,AK,AW,AY UnitsQuantity Rows...Fins/in Unit 48EJ,EK,EW,EY Physical Data 48EJ,EK,EW,EY Units06D537 06EA250 06EA265 Quantity...Type Ckt 1, Ckt Operating Weights Air Distribution Thru-the-Bottom Evaporator Fan Motor DataCombustion Fan Housing Location Install Flue HoodStages 48A,E Series Staged Gas ImplementationNumber of Stages Model Number Position Heat Size Htstgtyp Thermistor Designations Supply-Air Thermistor Connections Indoor Air Quality Sensor Configuration Make Electrical Connections DIP CCNCOM SIORLA LRA Unbalanced 3-Phase Supply VoltageElectrical Data 48AJ,AK,AW,AY Units Min MaxQty 30.8/28.0 180.5/177.7 225/225 236.3/230.9 MCA Mocp EW,EY Electrical Data 48EJ,EK,EW,EY UnitsRange Exhaust FAN Motor FLA LRAFLA LRA MCA Mocp EW,EY 54.0 23.6 41.6 RLA FLANEC GND Ground Field Power Wiring ConnectionsIFC CCBEquip GNDOFC Indoor-Fan Relay Terminal Block Carrier Comfort Network Indoor-Fan CircuitCCN IFC Pesc Color Code Recommendations CCN Connection Approved Shielded CablesSpace Temperature Averaging Wiring Make Outdoor-Air Inlet AdjustmentsAdding Seal Strip to Top of Hood Sides Adding Seal Strip to Sides of Hood Top Mounting Flange Mounting Angle With Tabs Attached to Filter Track Assembly Differential Enthalpy Control and Sensor Control Control Point Curve APPROX. DEG Psychrometric Chart for Enthalpy ControlBarometric Relief Damper and Power Exhaust Mounting Details 120.5 119.5 48EJ,EK,EW,EY058-068 Unit Size80.5 79.5 48EJ,EK,EW,EY024-054 Motormaster III Sensor Location 48EJ,EK,EW,EY054-064 Side Return Air Conversion Field ModificationsSTART-UP In. wg Pressure Control Signal VFD SET PointParameter Group Default Value Carrier Default Program Parameter ValuesMotor Standard Efficiency High Efficiency Typical Factory Wiring Optional Field Wiring Building Pressure Signal Level Closed DIP Switch ConfigurationSetting OpenAirflow DIP Switch Factory SettingsFan Performance, 48AJ,AK020-030 Vertical Discharge Units 18,000 Fan Performance, 48AJ,AK035 Vertical Discharge Units16,000 17,00017,000 18,000 19,000 20,000 Fan Performance, 48AJ,AK040,050 Vertical Discharge Units19,000 20,000Fan Performance, 48AJ,AK060 Vertical Discharge Units 11,000 12,000 13,000 14,000 15,000 Fan Performance, 48AW,AY020-030 Horizontal Discharge Units13,000 14,000 15,000 16,000 17,000 18,000 Fan Performance, 48AW,AY035 Horizontal Discharge Units17,000 18,000 16,000 17,000 18,000 19,000 20,000 Fan Performance, 48AW,AY040,050 Horizontal Discharge Units19,000 20,000 26,000 27,000 Fan Performance, 48AW,AY060 Horizontal Discharge UnitsFan Performance, 48EJ,EK024,034 Vertical Discharge Units 15,000 16,000 17,000 18,000 19,000 20,000 Fan Performance, 48EJ,EK038,044 Vertical Discharge Units19,000 20,000 Available External Static Pressure in. wg Rpm Bhp 000 1066 1096 1125000 1086 11.10 1114 11.61 1141 12.14 Fan Performance, 48EJ,EK048 Vertical Discharge UnitsRpm Bhp 10,000 949 13.81 970 14.54 990 15.26 Fan Performance, 48EJ,EK054-068 Vertical Discharge Units20,000 21,000 22,000 23,000 24,000 25,000 26,000 27,000 Fan Performance, 48EW,EY054-068 Horizontal Discharge Units26,000 27,000 Available External Static Pressure in. wg 10,000 956 12.99 976 13.66 996 14.32ESP Airflow LOW Speed Medium Speed High SpeedAir Quality Limits Motor LimitationsSequence of Operation Software Control Link Points User Defined Set PointsPage COM Common Heat Interlock Relay WiringInput Description Staged Gas System ComponentsStage Gas System Inputs/Outputs Function LocationNavigator Display Menu Structure Navigator DisplayCondition Occupied Morning Temperature Software HeatVersion Enabled DEG. F ResetField-Supplied Smoke Detector Wiring Stages Smoke Control ModesCooling Capacity Staging Table, CV Units with 2 Compressors Device Pressurization Smoke Purge Evacuation Fire ShutdownService Typical Gas Heating Section Manufacturer Lubricant LubricationCondenser-Fan Adjustment Evaporator Fan Service and ReplacementBelt Tension Adjustment To adjust belt tension Evaporator-Fan Motor ReplacementCooling Charging Chart 48EJ,EK,EW,EY024-034 Gas Valve AdjustmentCooling Charging Chart 48EJ,EK,EW,EY054-068 Protective Devices 20 HP 208/230-3-60 Voltage WireIndoor Voltage Wire 06D-537 208/230-3-60 Following fan motors have twoTypical 48EK VAV 24-V Control Circuit Typical CV 24-V Control Circuit Typical 48EK VAV 115-V Control Circuit Typical 48EJ CV 115-V Control Circuit 101 102 Troubleshooting Typical Refrigerant Circuiting 48AJ,AK,AW,AY027,030 Typical Refrigerant Circuiting 48AJ,AK,AW,AY035 Typical Refrigerant Circuiting 48EJ,EK,EW,EY038,044 Typical Refrigerant Circuiting 48AJ,AK,AW,AY040,050 Typical Refrigerant Circuiting 48EJ,EK,EW,EY048 Typical Refrigerant Circuiting 48EJ,EK,EW,EY054 Typical Refrigerant Circuiting 48AJ,AK,AW,AY060 Typical Refrigerant Circuiting 48EJ,EK,EW,EY064 Typical Refrigerant Circuiting 48EJ,EK,EW,EY068 IGC Control Heating and Cooling Control Board LED Alarms IGC Control Board LED AlarmsIAQ O Channel Designations Base Module CVO Channel Designations Base Module VAV Terminal no AssignmentService Training START-UP Checklist General
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48EJ, 48AJ, 48AK, 48EK, 48AY020-060 specifications

The Carrier 48EJ, 48AW, 48EK, 48AJ, and 48EY024-068 are cutting-edge rooftop air conditioning units designed for commercial applications. These models are renowned for their reliability, energy efficiency, and innovative technologies aimed at providing optimal indoor comfort.

One of the standout features of these units is their advanced cooling and heating capabilities. They employ a multi-stage compressor system that allows for precise temperature control, accommodating various load requirements. This flexibility is particularly beneficial in commercial settings where the cooling load can fluctuate throughout the day.

Energy efficiency is paramount in today’s environmental landscape, and Carrier has ensured that these models meet stringent efficiency standards. They incorporate high-efficiency scroll compressors, which significantly reduce energy consumption while delivering powerful performance. The units are also equipped with variable speed fans that adjust airflow based on demand, further optimizing energy use.

In terms of construction, these rooftop units feature a robust design that enhances durability and longevity. The cabinet is constructed to withstand harsh weather conditions, ensuring reliable performance year-round. Additionally, the units are equipped with corrosion-resistant coatings, particularly useful in coastal environments where salt exposure can be a concern.

The Carrier 48EJ, 48AW, 48EK, 48AJ, and 48EY models utilize advanced controls and connectivity features, allowing for easy integration into building management systems. This connectivity enables remote monitoring and control, facilitating quick response to changing conditions and simplifying maintenance tasks.

Noise reduction is another key characteristic of these models. They are designed with sound-absorbing insulation and low-noise fan blades to ensure quiet operation, making them suitable for noise-sensitive environments such as schools and hospitals.

These units are also available with various options for air filtration and dehumidification. The use of high-efficiency air filters enhances indoor air quality by trapping dust, pollen, and other airborne particles. Enhanced dehumidification capabilities ensure that spaces remain comfortable even in humid conditions.

In conclusion, the Carrier 48EJ, 48AW, 48EK, 48AJ, and 48EY024-068 rooftop units are engineered to offer exceptional performance, energy efficiency, and durability. With their advanced technologies and user-friendly features, they stand out as reliable solutions for meeting diverse commercial cooling and heating needs, making them a popular choice for many businesses.