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Carrier 48EZ-A Refrigerant Circuit, High-PressureSwitch, Explosion Hazard, 48EZ --A

Models: 48EZ-A

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Fig. 25 - Refrigerant Circuit

48EZ -- A

C99097

Fig. 25 - Refrigerant Circuit

2.Disconnect leads on switch.

3.Apply ohm meter leads across switch. You should have continuity on a good switch.

NOTE: Because these switches are attached to refrigeration system under pressure, it is not advisable to remove this device for troubleshooting unless you are reasonably certain that a problem exists. If switch must be removed, remove and recover all system charge so that pressure gauges read 0 psi. Never open system without breaking vacuum with dry nitrogen.

High-Pressure Switch

The high-pressure switch is located in the discharge line and protects against excessive condenser coil pressure. It opens at 650 psig.

High pressure may be caused by a dirty outdoor coil, failed fan motor, or outdoor air recirculation. To check switch:

1.Turn off all power to unit.

2.Disconnect leads on switch.

3.Apply ohm meter leads across switch. You should have continuity on a good switch.

Copeland Scroll Compressor (Puron Refrigerant)

The compressor used in this product is specifically designed to operate with Puron (R-410A) refrigerant and cannot be interchanged.

The compressor is an electrical (as well as mechanical) device. Exercise extreme caution when working near compressors. Power should be shut off, if possible, for most troubleshooting techniques. Refrigerants present additional safety hazards.

!WARNING

EXPLOSION HAZARD

Failure to follow this warning could result in personal injury or death and/or property damage.

Wear safety glasses and gloves when handling refrigerants. Keep torches and other ignition sources away from refrigerants and oils.

The scroll compressor pumps refrigerant throughout the system by the interaction of a stationary and an orbiting scroll. The scroll compressor has no dynamic suction or discharge valves, and it is more tolerant of stresses caused by debris, liquid slugging, and flooded starts. The compressor is equipped with an internal pressure relief port. The pressure relief port is a safety device, designed to protect against extreme high pressure. The relief port has an operating range between 550 and 625 psig differential pressure.

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Carrier 48EZ-A Refrigerant Circuit, High-PressureSwitch, Copeland Scroll Compressor Puron Refrigerant, Explosion Hazard

Contents

TABLE OF CONTENTS SAFETY CONSIDERATIONSFig. 1 - Unit 48EZ-A Installation InstructionsRECEIVING AND INSTALLATION Installation on older “G” series roof curbsINTRODUCTION Step 1 — Check EquipmentA09450 Fig. 2 - 48EZ-A24-36Unit Dimensions48EZ --A A09451 Fig. 3 - 48EZ-A42-60Unit Dimensions48EZ --A Fig. 4 - Roof Curb Dimensions SMALL CURBROOF CURB DETAIL LARGE CURBACCESS PANELS MUST BE IN PLACE WHEN RIGGING Step 5 — Rig and Place UnitStep 4 — Provide Clearances Fig. 5 - 48EZ-ASuggested RiggingStep 7 — Install Flue Hood Step 8 — Install Gas PipingStep 6 — Connect Condensate Drain InspectionTEE NIPPLE CAP FIRE OR EXPLOSION HAZARDFig. 7 - Sediment Trap 48EZ --ATable 1 – Physical Data - Unit 48EZ-A 48EZ --ATable 1 - Physical Data - Unit 48EZ-ACont’d Table 2 – Maximum Gas Flow CapacityTable 3 – Heating Inputs 48EZ --AStep 9 — Install Duct Connections Configuring Units for Downflow Vertical DischargeAlternate Method UNIT COMPONENT DAMAGE HAZARDReturn Duct Panels Return & Supply Duct Panels fromUnderside of Base Alternate Method Fig. 8 - Supply and Return Duct OpeningStep 10 — Install Electrical Connections Special Procedures for 208-VOperationHigh-VoltageConnections Control Voltage ConnectionsBalance Point Setting-Thermidistator Hybrid PRE-START-UP48EZ ThermostatStep 3 - Start-upHeating and Make Adjust- ments Fig. 11 - Burner AssemblySTART-UP Step 1 — Check for Refrigerant LeaksAdjust Gas Input Check Heating ControlCheck Gas Input Fig. 12 - Monoport BurnerAirflow and Temperature Rise Limit SwitchesRollout Switch Check Burner FlameStep 4 - Start-upCooling and Make Adjust- ments Checking and Adjusting Refrigerant ChargeIndoor Airflow and Airflow Adjustments Checking Cooling Control OperationGas Heating Fan Speed Set-up Continuous Fan OperationTable 6 – Color Coding for Indoor Fan Motor Leads Fig. 14 - Interface Fan Board IFBTable 7 – Filter Pressure Drop Table IN. W.C Table 8 – 48EZ-AWet Coil Pressure Drop IN. W.C48EZ --A FILTER SIZE48EZ --A Heating48EZ --A 123448EZ --A 140248EZ --A 1445Fig. 15 - 208/230-1-60Wiring Diagram, Unit 48EZ-A 48EZ AA09209 Fig. 16 - 208/230-3-60Wiring Diagram, Unit 48EZ-A48EZ --A A08019 Fig. 17 - Cooling Charging Table-Subcooling48EZ --A MAINTENANCE Cleaning the Blower Motor and WheelAir Filter Indoor Blower and MotorLimit Switch Induced Draft combustion air Blower AssemblyFig. 18 - Blower Housing and Flue Collector Box Fig. 19 - Unit Access PanelsElectrical Controls and Wiring Outdoor FanRefrigerant Circuit Fig. 20 - Removal of Motor and Blower WheelPage High-PressureSwitch Fig. 25 - Refrigerant CircuitCopeland Scroll Compressor Puron Refrigerant EXPLOSION HAZARDUNIT OPERATION AND SAFETY HAZARD LEGENDRefrigerant System Compressor OilTROUBLESHOOTING START-UPCHECKLISTSynthetic Roof Precautionary Procedure Liquid Line Filter DrierSYMPTOM 48EZ --A48EZ --A Table 12 – Troubleshooting Guide–HeatingTable 13 – Troubleshooting Guide–LEDError Codes TEMPERATURES Remove and Store in Job FilesI. PRELIMINARY INFORMATION MODEL NO PRESSURES48EZ --A Catalog No: 48EZ---06SIEdition Date: 08/09 Replaces: 48EZ---05SI