Ruud air conditioner troubleshooting

SYMPTOMPOSSIBLE CAUSEREMEDY
Unit will not run• Power off or loose electrical connection• Check for correct voltage at line voltage connections in condensing unit.
• Thermostat out of calibration set too high• Reset.
• Defective control board• Check control board diagnostic codes.
• Blown fuses/tripped breaker• Replace fuses/reset breaker.
• Transformer defective• Check wiring. Replace transformer.
• High-pressure control open• Reset. Also see high head pressure remedy. The highpressure control opens at 610 PSIG.
• Miswiring of communications (communication light on continuously)• Check communication wiring.
Outdoor fan runs, compressor doesn't• Run or start capacitor defective• Replace.
• Start relay defective• Replace.
• Loose connection• Check for correct voltage at compressor. Check and tighten all connections.
• Compressor stuck, grounded or open motor winding, open internal overload.• Wait at least 3 hours for overload to reset. If still open, replace the compressor.
• Low-voltage condition• Add start kit components.
Insufficient cooling• Improperly sized unit• Recalculate load.
• Improper indoor airflow• Check. Should be approximately 400 CFM per ton.
• Incorrect refrigerant charge• Charge per procedure attached to unit service panel.
• Air. noncondensibles, or moisture in system• Recover refrigerant. Evacuate and recharge. Add filter drier.
Compressor short cycles• Incorrect voltage• At compressor terminals, voltage must be ± 10% of nameplate marking when unit is operating.
• Defective overload protector• Replace. Check for correct voltage.
• Refrigerant undercharge• Add refrigerant.
Registers sweat• Low indoor airflow• Increase speed of blower or reduce restriction. Replace air filter.
High head, low vapor pressures• Restriction in liquid line, expansion device, or filter drier• Remove or replace defective component.
• Bad TXV• Replace TXV.
High head, high or normal vapor pressure Cooling mode• Dirty outdoor coil• Clean coil.
• Refrigerant overcharge• Correct system charge.
• Outdoor fan not running• Repair or replace.
• Air or noncondensibles in system• Recover refrigerant. Evacuate and recharge.
Low head, high vapor pressures• Bad TXV• Replace TXV.
• Bad compressor• Replace compressor.
Low vapor, cool compressor, iced indoor coil• Low indoor airflow• Increase speed of blower or reduce restriction. Replace air filter.
• Operating below 65°F outdoors• Add Low Ambient Kit.
• Moisture in system• Recover refrigerant. Evacuate and recharge. Add filter drier.
High vapor pressure• Excessive load• Recheck load calculation.
• Defective compressor• Replace.
Fluctuating head and vapor pressures• TXV hunting• Check TXV bulb clamp. Check air distribution on coil. Replace TXV.
• Air or noncondensibles in system• Recover refrigerant. Evacuate and recharge.
Gurgle or pulsing noise at expansion device or liquid line• Air or noncondensibles in system• Recover refrigerant. Evacuate and recharge.
High superheatLow chargeCheck system charge.
(greater than 15°F [-9°C] at coil)Faulty metering deviceRestricted cap tube. TEV (TXV)
Power element superheat out of adjustment internally
Foreign matter stopping flow
High internal loadHot air (attic) entering return
Heat source on: misfired or faulty control
Restriction in liquid lineDrier plugged.
Line kinked.
Low head pressureLow charge
Operating in low ambient temperatures
Suction or liquid line subjected to high heat sourceHot attic
Hot water line
Low line voltageLoose wire connectionsCheck wiring.
Power company problem, transformerHave problem corrected before diagnosis continues.
Undersized wire feeding unitCorrect and complete diagnosis.
High line voltagePower company problemHave problem corrected.
High head pressureOverchargeCheck system charge.
Dirty heat pump coilClean coil.
Faulty or wrong size heat pump fan motorReplace fan motor.
Faulty fan blade or wrong rotationReplace fan blade.
Replace with correct rotation motor.
Recirculation of airCorrect installation.
Additional heat sourceCheck for dryer vent near unit.
Check for recirculation from other equipment.
NoncondensiblesRecover refrigerant. Evacuate and recharge system.
Equipment not matchedCorrect mismatch.
Short cycling of compressorFaulty pressure controlReplace pressure control.
Loose wiringCheck unit wiring.
ThermostatLocated in supply air stream
Differential setting too close
Customer misuse
TEVInternal foreign matter
Power element failure
Valve too small
Distributor tube/tubes restricted
Distributor tubeRestricted with foreign matter
Kinked
I.D. reduced from previous compressor failure
Short cycling of compressor (cont.)Low chargeCheck system charge.
Low evaporator airflowDirty coil
Dirty filter
Duct too small or restricted
Faulty run capacitorReplace.
Faulty internal overloadReplace compressor.
Faulty Compressor ValvesFast equalization/Low pressure differenceReplace compressor and examine system to locate reason.
Voltage present Compressor start componentsCheck start capacitor.
Check potential relay.
Run capacitorCheck with ohmmeter
Internal overloadAllow time to reset.
Compressor windingsCheck for correct ohms.
Voltage present on line side of compressor contactor onlyThermostatCheck for control voltage to contactor coil.
Compressor control circuitHigh-pressure switch
Low-pressure switch
Ambient thermostat
Solid-state protection control or internal thermal sensors
Compressor timed off/on control or interlock
No voltage on line suede of compressor contactorBlown fuses or tripped circuit breakerCheck for short in wiring or unit.
Improper wiringRecheck wiring diagram.
Improper voltageHigh voltageWrong unit
Power supply problem
Low voltageWrong unit
Power supply problem
Wiring undersized
Loose connections
Single Phasing (3 phase)Check incoming power and fusing.
MoisturePoor evacuation on installation or during serviceIn each case, the cure is the same. Recover refrigerant. Add filter drier, evacuate, and recharge.
High head pressureNoncondensibles air
Unusual head and suction readingsWrong refrigerant or mixed refrigerants
Foreign matter copper filingsCopper tubing cuttings
Copper oxideDirty copper piping or nitrogen not used when brazing
Welding scaleNitrogen not used during brazing
Soldering fluxAdding flux before seating copper partway
Excess soft solderWrong solder material
Compressor failuresLine tubing too largeReduce pipe size to improve oil return.
Low suction pressureLow chargeCheck system charge.
Refrigerant leaksRepair and recharge.
Cold, noisy compressor SluggingDilution of oil with refrigerantObserve piping guidelines.
Noisy compressorMigrationCheck crankcase heater.
Cold, sweating compressorFloodingCheck system charge.
Low loadReduced airflowDirty filter
Dirty coil
Wrong duct size
Restricted duct
Thermostat settingAdvise customer.
Short cycling of compressorFaulty highor low-pressure controlReplace control.
Loose wiringCheck all control wires.
ThermostatIn supply air stream, out of calibration
Customer misuse
On start-upIncorrect pipingReview pipe size guidelines.
TEV hunting when runningFaulty TEVReplace TEV.
Poor system control using a TEVLoose sensing bulbSecure the bulb and insulate.
Bulb in wrong locationRelocate bulb.
Wrong size TEVUse correct replacement.
Improper superheat setting (less than 5®F [-15°CDReplace TEV.
High Superheat. Low Suction Pressure (superheat over 15*F [-9*CDMoisture freezing and blocking valveRecover charge, install filter-drier, evacuate system, recharge.
Dirt or foreign material blocking valveRecover charge, install filter-drier, evacuate system, recharge.
Low refrigerant chargeCorrect the charge.
Vapor bubbles in liquid lineRemove restriction in liquid line. Correct the refrigerant charge.
Remove noncondensible gases.
Size liquid line correctly.
Misapplication of internally equalized valveUse correct TEV.
Plugged external equalizer lineRemove external equalizer line restriction.
Undersized TEVReplace with correct valve.
Loss of charge from power head sensing bulbReplace power head or complete TEV.
Charge migration from sensing bulb to power head (Warm power head with warm, wet cloth. Does valve operate correctly now?)Ensure TEV is warmer than sensing bulb.
Valve feeds too much refrigerant, with low superheat and higher than normal suction pressureMoisture causing valve to stick open.Recover refrigerant, replace filter-drier, evacuate system, and recharge.
Dirt or foreign material causing valve to stick openRecover refrigerant, replace filter drier, evacuate system, and recharge.
TEV seat leak (a gurgling or hissing sound is heard AT THE TEV during the off cycle, if this is the cause). NOT APPUCABLE TO BLEED PORT VALVES.Replace the TEV.
Oversized TEVInstall correct TEV.
Incorrect sensing bulb locationInstall bulb with two mounting straps, in 2:00 or 4:00 position on suction line, with insulation.
Low superheat adjustmentReplace TEV.
Incorrectly installed, or restricted external equalizer lineRemove restriction, or relocate external equalizer.
Compressor flood back upon start-upRefrigerant drainage from flooded evaporatorInstall trap riser to the top of the evaporator coil.
Inoperable crankcase heater or crankcase heater neededReplace or add crankcase heater.
Any of the causes listed under symptoms of Electrical problems on page 45Any of the solutions listed under solutions of Electrical problems on page 45
Superheat rs low to normal with low suction pressureUnequal evaporator circuit loadingEnsure airflow is equally distributed through evaporator.
Check for blocked distributor tubes.
Low load or airflow entering evaporator coilEnsure blower is moving proper air CFM.
Remove/Correct any airflow restriction.
Superheat and suction pressure fluctuate (valve is hunting)Expansion valve is oversizedInstall correct TEV.
Sensing bulb is affected by liquid refrigerant or refrigerant oil flowing through suction lineRelocate sensing bulb in another position around the circumference of the suction line.
Unequal refrigerant flow through evaporator circuitsEnsure sensing bulb is located properly.
Check for blocked distributor tubes.
Moisture freezing and partially blocking TEVRecover refrigerant, change filter-drier, evacuate system, and recharge.
Valve does not regulate at allExternal equalizer line not connected or line pluggedConnect equalizer line in proper location, or remove any blockage.
Sensing bulb lost its operating chargeReplace TEV.
Valve body damaged during soldering or by improper installationReplace TEV.