Carrier 48EZ(N)-A Installation Instructions Manual

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Contents

39Table 12 – Troubleshooting Guide -- Cooling or Heat Pump Heating ModeSYMPTOM CAUSE REMEDYCompressor and Outdoor fan will notstart.Power Failure Call power company.Fuse blown or circuit breaker tripped Replace fuse or reset circuit breaker.Defective thermostat, contactor, transformer, or controlrelay Replace component.Insufficient line voltage Determine cause and correct.Incorrect or faulty wiring Check wiring diagram and rewire correctly.Thermostat setting too high Lower thermostat setting below room temperature.Compressor will not start but Outdoorfan runs.Faulty wiring or loose connections in compressor circuit Check wiring and repair or replace.Compressor motor burned out, seized, or internal over-load open Determine cause Replace compressor.Defective run/start capacitor, overload, start relay Determine cause and replace.One leg of 3 ---phase power dead Replace fuse or reset circuit breaker. Determinecause.Three --- phase scroll compressor makesexcessive noise, and there maybe a low pressure differential.Scroll compressor is rotating in the wrong direction Correct the direction of rotation by reversing the3 ---phase power leads to the unit.Compressor cycles (other than normallysatisfying thermostat).Refrigerant overcharge or undercharge Recover refrigerant, evacuate system, and rechargeto capacities shown on nameplate.Defective compressor Replace and determine cause.Insufficient line voltage Determine cause and correct.Blocked Outdoor Determine cause and correct.Defective run/start capacitor, overload or start relay Determine cause and replace.Defective thermostat Replace thermostat.Faulty Outdoor ---fan motor or capacitor Replace.Damaged reversing valve Determine cause and correctRestriction in refrigerant system Locate restriction and remove.Compressor operates continuously.Dirty air filter Replace filter.Unit undersized for load Decrease load or increase unit size.Thermostat set too low Reset thermostat.Low refrigerant charge Locate leak, repair, and recharge.Mechanical damage in compressor. Replace compressor.Air in system Recover refrigerant, evacuate system, and recharge.Frosted coil with incorrect defrost operationCheck defrost time settings, Reset as necessaryCheck defrost temperature switch, Replace as nec-essaryOutdoor coil dirty or restricted Clean coil or remove restriction .Excessive head pressure.Dirty air filter Replace filter.Dirty Indoor or Outdoor coil Clean coil.Refrigerant overcharged Recover excess refrigerant.Air in system Recover refrigerant, evacuate system, and recharge.Indoor or Outdoor air restricted or air short---cycling Determine cause and correct.Head pressure too low.Low refrigerant charge Check for leaks, repair, and recharge.Compressor IPR leaking Replace compressor.Restriction in liquid tube Remove restriction.Excessive suction pressure.High heat load Check for source and eliminate.Compressor IPR leaking Replace compressor.Refrigerant overcharged Recover excess refrigerant.Reversing valve hung up or leaking internally Replace valveSuction pressure too low.Dirty air filter Replace Filter.Low refrigerant charge Check for leaks, repair, and recharge.Metering device or low side restricted Remove source of restriction.Insufficient Indoor airflow Increase air quantity. Check filter — replace if neces-sary.Temperature too low in conditioned area Reset thermostat.Outdoor ambient below 55°F (12.8°C) Install low---ambient kit.Field---installed filter ---drier restricted Replace.(Heat) Outdoor coil frosted Move timer on control board to 30 minutes betweendefrost cyclesCompressor runs but outdoor fan doesnot NC (normally closed) contacts on defrost board open Check condition of relay on board Replace if neces-sary48EZ -- A

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