Carrier 48HE003---006, 48HJ004---007 Routine 3 OAT, DX Cooling Temperature Control Example

Page 48

48HE,HJ

SIf SAT > SASP + 5 and economizer position >80%, economizer will go to minimum position for 3 minutes or until SAT > 68_F.

SIf compressor one is on then second stage of mechanical cooling will be energized; otherwise the first stage will be energized.

SIntegrator resets.

SEconomizer opens again and controls to SASP after stage one on for 90 seconds.

Routine 3 (OAT > 68)

SEconomizer is opened 100%.

SCompressors 1 and 2 are cycled based on Y1 and Y2 using minimum on and off times and watching the supply air temperature as compared to SATLO1 and SATLO2 set points.

If optional power exhaust is installed, as the outdoor-air damper opens and closes, the power exhaust fans will be energized and deenergized.

If field-installed accessory CO2 sensors are connected to the PremierLinkcontrol, a PID-controlled demand ventilation strategy will begin to operate. As the CO2 level in the zone increases above the CO2 set point, the minimum position of the damper will be increased proportionally. As the CO2 level decreases because of the increase in fresh air, the outdoor-air damper will be proportionally closed.

HEATING - UNITS WITH ECONOMI$ER2, PREMIER- LINK CONTROL AND A THERMOSTAT

When the thermostat calls for heating, terminal W1 is energized. The PremierLink control will move the economizer damper to the minimum position if there is a call for G and closed if there is a call for W1 without G. In order to prevent thermostat from short cycling, the unit is locked into the heating mode for at least 10 minutes when W1 is energized. The induced-draft motor is then energized and the burner ignition sequence begins.

On units equipped for two stages of heat, when additional heat is needed, W2 is energized and the high-fire solenoid on the main gas valve (MGV) is energized. When the thermostat is satisfied and W1 is deenergized, the IFM stops after a 45-second time-off delay unless G is still maintained.

COOLING - UNITS WITH ECONOMI$ER2, PREMIER- LINK CONTROL AND A ROOM SENSOR

When free cooling is not available, the compressors will be controlled by the PremierLink controller using a PID Error reduction calculation as indicated by Fig 51.

The PremierLink controller will use the following information to determine if free cooling is available:

SIndoor fan has been on for at least 30 seconds.

SThe SPT, SAT, and OAT inputs must have valid readings.

SOAT must be less than 75_F. S OAT must be less than SPT.

SEnthalpy must be LOW (may be jumpered if an enthalpy sensor is not available).

SEconomizer position is NOT forced.

 

 

TEMPERATURE CONTROL

TEMPERATURE

75

 

74

 

73

 

72

SET POINT

71

TEMPERATURE

70

 

SPACE

 

69

 

68

 

 

 

 

 

TIME

NOTE: PremierLink control performs smart staging of 2 stages of DX cooling and up to 3 stages of heat.

C06042

Fig. 51 ---DX Cooling Temperature

Control Example

 

 

TEMPERATURE CONTROL

TEMPERATURE

75

 

74

 

73

 

72

COOL SETPOINT

71

TEMPERATURE

70

HEAT SETPOINT

SPACE

69

 

68

 

 

 

 

 

TIME

 

 

C06043

Fig. 52 ---Economizer Temperature

Control Example

When free cooling is available, the outdoor-air damper is positioned through the use of a Proportional Integral (PID) control process to provide a calculated supply-air temperature into the zone. The supply air will maintain the space temperature between the heating and cooling set points as indicated in Fig. 52.

The PremierLink control will integrate the compressor stages with the economizer based on similar logic as the three routines listed in the previous section. The SASP will float up and down based on the error reduction calculations that compare space temperature and space set point.

When outside-air temperature conditions require the economizer to close for a compressor stage-up sequence, the economizer control integrator is reset to zero after the stage-up sequence is completed. This prevents the supply-air temperature from dropping too quickly and creating a freeze condition that would make the compressor turn off prematurely.

The high space set point is used for DX (direct expansion) cooling control, while the economizer space set point is a calculated value between the heating and cooling set points. The economizer set point will always be at least one degree below the cooling set point, allowing for a smooth transition from mechanical cooling with economizer assist, back to economizer cooling as the cooling set point is achieved. The compressors may be used for initial cooling then the PremierLink controller will modulate the economizer using an error reduction calculation to hold the space temperature between the heating and cooling set points. (See Fig. 52.)

The controller uses the following conditions to determine economizer cooling:

SEnthalpy is Low

SSAT reading is available S OAT reading is available

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Contents Installation Instructions Electrical Shock HazardFIRE, Explosion Hazard Roof CurbAlternate Unit Support 48HE,HJ Install Flue Hood Property Damage HazardPositioning Unit Operating Dimensions Weight 48HE48HJ 48HJ004-007 Base Unit Dimensions 48HE003-006 Base Unit Dimensions Field power supply Field control wiringHeat anticipator settings Physical Data 48HJ Nominal CapacityHJE HJD Physical Data 48HE HEE HED Power Wiring Connections Electrical Data 48HE 48HE003---006Electrical Data 48HJ 38.2 242 208/230---3---60 187 254 12.4 Assembly HUMIDI-MIZERADAPTIVE Dehumidification SystemManual outdoor damper Convenience outletTypical Humidi-MiZer t Adaptive Dehumidification System Install the Supply Air Temperature SAT Sensor Outdoor Air Temperature Sensor OATInstall the Indoor Air Quality CO2 Sensor Enthalpy Sensors and ControlPremierLinkSensor Usage PremierLink ControllerPremierLinktController Installed Return Air Enthalphy Sensor EconoMi$er IV Component LocationsOutdoor Air Temperature OAT Sensor ECONOMI$ER IV Standard SensorsECONOMI$ER IV Control Modes EconoMi$er IV Wiring RUNExhaust Set Point Adjustment Differential Enthalphy ControlIndoor Air Quality IAQ Sensor Input Minimum Position Control ThermostatsDamper Movement Enthalpy Changeover Set Points Demand Controlled Ventilation DCVAdjust Evaporator-Fan Speed Dehumidification of Fresh Air with DCV ControlBelt drive motors CO2Sensor Standard Settings Belt Drive Motor Mounting48HJ Fan Rpm at Motor Pulley Setting With High-Static Motor Accessory static pressureEvaporator-Fan Motor Data Standard Motor Evaporator-Fan Motor Data High-Static Motors48HJ Outdoor Sound Power Total Unit 48HE Outdoor Sound Power Total UnitUnit ARI Octave Bands Rating AirflowRpm Bhp 11001200 1300Rpm Bhp Watts Rpm Bhp Watts Watts Rpm Bhp 12001600 1700Rpm Bhp Watts 1500 1642 2333 1704Watts Rpm Bhp 1800 26002700 2800Bhp Watts Rpm 2700 2800 2900 3000Bhp 600 Bhp Watts 900 Watts RpmWatts Rpm Bhp 900 1700 1800 1900 2000 Bhp Watts1900 2000 2100 2200 2300 2400 2500 800 350 904 438 999 535 1087 640 1169 753 913 569 1250 1500 1750 2000 2250 2500 2750 3000 Internal Wiring Refrigerant Service PortsUnit Preparation Gas PipingCooling Main BurnersHeating Safety Relief Ventilation Continuous FanOperating Sequence Cooling units without economizer Heating units without economizerDX Cooling Temperature Control Example Routine 3 OATSubcooling Mode Units with HUMIDI-MIZERADAPTIVE Dehumidification SystemNormal Design Operation Cleaning Evaporator CoilCondenser coil One-Row CoilsCondenser-Fan Adjustment High Pressure SwitchFilters Lubrication CompressorHUMIDI-MIZERSYSTEM Charging Cooling Charging Chart Standard 48HJ006 To USE Cooling Charging CHART, Standard Unit Flue Gas Passageways Combustion-Air BlowerLimit Switch LED Error Code DescriptionRemoval and Replacement of GAS Train See Burner IgnitionReplacement Parts LOW HeatOFM Unit Troubleshooting Economi$er IV TroubleshootingDcv demand controlled ventilation and power exhaust Economi$er IV troubleshooting completionLED Error Code Service Analysis Symptom Cause RemedyComponent Damage Hazard LED OFFHeating Service Analysis Problem Cause RemedyCooling Service Analysis EconoMi$er IV Input/Output Logic Inputs OutputsSTART-UP Checklist

48HJ004---007, 48HE003---006 specifications

Carrier has long been a trusted name in the HVAC industry, and its models 48HJ004---007 and 48HE003---006 continue that legacy, offering efficient, reliable climate control solutions. These models are designed for different applications, ensuring optimal performance in a variety of environments.

The 48HJ series features advanced rooftop units that are ideal for commercial settings. They come equipped with high-efficiency scroll compressors that provide superior cooling and heating capabilities. This series is noted for its compact design, allowing for easy installation on rooftops or other constrained spaces. The units offer variable capacity operation, which enables them to efficiently meet varying heating and cooling demands without unnecessary energy consumption.

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In conclusion, Carrier 48HJ004---007 and 48HE003---006 models are designed with cutting-edge technology, energy efficiency, and flexibility in mind. Their robust features make them ideal choices for commercial applications, providing reliable comfort and operational excellence. Whether for cooling or heating, these systems stand out in performance and sustainability, earning Carrier's reputation as a leader in the HVAC market.