Carrier EK, 48EJ, EW, EY024-048 installation instructions Com, Hir, DEG. F Reset

Page 42

MORNING WARM-UP (VAV Only) (Stand-Alone Opera- tion) Ð When the unit operates in stand-alone mode, morn- ing warm-up occurs when the unit is energized in Occupied mode and return-air temperature (RAT) is below 68 F. Warm-up will not terminate until the RAT reaches 68 F. The heat in- terlock relay output is energized during morning warm-up. (A ®eld-installed 24-vdc heat interlock relay is required.) The output will be energized until the morning warm-up cycle is complete. Refer to Fig. 42 for heat interlock relay wiring.

SPACE TEMPERATURE RESET SENSOR (VAV Only) Ð An accessory space temperature sensor wired to terminals T1 and T2 on the control module is required. Space tem- perature reset is used to reset the supply-air temperature set point of a VAV system higher, as the space temperature falls below the Occupied Cool set point. As the space tempera- ture falls below the Occupied Cool set point, the supply-air temperature will be reset upward as a function of the reset ratio. (Default is 3.) Reset ratio is expressed in degrees change

in supply-air temperature per degree of space temperature change. A reset limit will exist which will limit the maxi- mum number of degrees the supply-air temperature may be raised. (Default is 10 F.) Both the reset ratio and the reset limit are user de®nable. The sequence of operation is as follows:

1.The on/off status of the unit supply fan is determined.

2.If the fan is ``on,'' the sequence will check if the system is occupied.

3.If the system is occupied, the sequence will determine if the reset option is enabled.

4.If the reset option is enabled, the sequence will read the space temperature and compare it to the Occupied Cool set point. If the temperature is below the Occupied Cool set point, the algorithm will compute the reset value and compare this value against the reset limit. If it is greater than the reset limit, the sequence will use the reset limit as the reset value.

CB4

3.2 AMPS

BASE MODULE

CONTROL BOARD

INDOOR FAN RELAY COM

T

30

T29

T

28

TRAN2

B COM

SECONDARY

24 VOLT

 

LEGEND

CB

Ð Circuit Breaker

COM

Ð Common

HIR

Ð

Heat Interlock Relay

T

Ð

Terminal

TRAN Ð Transformer

HIR

FIELD

INSTALLED

(HN61KK040)

(24V, 9.5VA)

Fig. 42 Ð Heat Interlock Relay Wiring

BASE MODULE

CONTROL BOARD

(+) T11

(–) T12

LEGEND

T Ð Terminal

4-20 mA

INPUT

FIELD

SUPPLIED

INPUT DEVICE

mA INPUT

DEG. F RESET

4

0.00

5

1.25

6

2.50

7

3.75

8

5.00

9

6.25

10

7.50

11

8.75

12

10.00

13

11.25

14

12.50

15

13.75

16

15.00

17

16.25

18

17.50

19

18.75

20

20.00

NOTE: The 4 to 20 mA input is a ®eld-supplied non-

Carrier EMS (Energy Management System) device.

Fig. 43 Ð Space Temperature Reset Wiring

42

Image 42
Contents Installation, Start-Up Service Instructions Field Fabricate Ductwork Instructions onUnit Leveling Tolerances Dimensions Degrees and InchesRoof Curb Sizes Weight Unit OperatingSize 48EJ,EKD044 Ft-in 48EJ,EKD03848EJE038 48EJE044Base Unit Dimensions, 48EW,EY024-034 Base Unit Dimensions, 48EW,EY038-048 48EJ,EK,EW,EYD034 Unit Weight 48EJ,EK,EW,EYD02448EJ,EK,EW,EYD028 48EJ,EK,EW,EYD030 48EJ,EK,EW,EYD038Physical Data Unit 48EJ,EK,EW,EY4442/4602 4668/4828 4955/5115 Air Distribution Ð Thru-the-Bottom Combustion Fan Housing Location Unit Configuration Default Cooling Default Heating VAVField Control Remote Start/Stop Make Electrical Connections CCN SIOLED Electrical Data RLA LRAFLA LRA MCA Mocp Hacr FLA LRAFLA NECHeating, Air Conditioning Qty044 Minimum Circuit AmpsGND Ð Ground Terminal BlockDIP PEC2413 or CCN Connection Approved Shielded CablesManufacturer Cable Part no 8772RED Make Outdoor-Air Inlet AdjustmentsColor Code Recommendations WhiteAdding Seal Strip to Top of Hood Sides Adding Foam Strip to Hood Side Mounting Angle With Tabs Attached to Filter Track Assembly Psychrometric Chart for Enthalpy Control Barometric Relief Damper and Power Exhaust Mounting Details Pressure Transducer Locations START-UP VFD Supply Air Pressure Set Point Pressure Control VFDSET Point Building Pressure Signal Level Direct Digital Controls DIP Switch ConguraPotentiometer Signal Levels VdcPower Exhaust Default Set Points DIP Switch CongurationDIP Switch Factory Settings Airflow 18,000 16,00017,000 19,000528 572 615 656 695 733 769 805 ESP Fan Performance Ð Power ExhaustMotor Limitations Standard Efficiency MotorsSequence of Operation Air Quantity LimitsUser Dened Set Points GAS HEATING, Variable AIR Volume VAV Units DEG. F Reset COMHIR Smoke Control Modes Device Pressurization Smoke Purge Evacuation Fire ShutdownCooling Capacity Staging Table, CV Units With 2 Compressors StagesCompressor Lubrication Manufacturer LubricantEvaporator Fan Service and Replacement Typical Gas Heating SectionEvaporator-Fan Motor Replacement Condenser-Fan AdjustmentBelt Tension Adjustment Protective DevicesGas Valve Ifcb AHAIFC TranTypical Power Schematic 48EJ,EK,EW,EY024-034 208/230-3-60 Typical VAV 115-v Control Circuit Typical CV 115-v Control Circuit Typical VAV 24-v Control Circuit Typical CV 24-v Control Circuit Troubleshooting Typical Refrigerant Circuiting 48EJ,EK,EW,EY038,044 Typical Refrigerant Circuiting 48EJ,EK,EW,EY048 IGC Control Heating and Cooling IGC Control Board LED Alarms Control Board LED AlarmsTerminal no Assignment I/O Channel Designations Base Module Ð CVI/O Channel Designations Base Module Ð VAV SPTPackaged Service Training START-UP Checklist General
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EW, EY024-048, EK, 48EJ 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.

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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.

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