Troubleshooting
Air Conditioner Problem
Problem / Symptoms:
  1. Unit is not running
  2. Unit is running but warm air is coming out
  3. Not enough cool air is coming out and interior room temperature is higher than before
  4. Compressor is running but no air is coming out
  5. Some rooms are warm but other rooms are cool
  6. There’s smoke or burning smell from the air coming out
  7. Fuse is blown and unit is not working
  8. Electric circuit breaker switch is off and compressor stopped
  9. Air conditioner is making lot of noise
  10. Water leaks when air conditioner is running
  11. Compressor is hot and cannot be started

A. Unit is not running
Possible cause: (each cause has matching repair)
  1. Fuse has blown or breaker switch is off
  2. Electrical wire burned
  3. 24 volt transformer burned or 24 volt fuse blown
  4. Defective thermostat
  5. In case of high pressure control, reset switch is turned off

Check and repair:
  1. Remove fuse box switch and replace fuse. Turn on the switch. If fuse blows again soon after, there's problem with running capacitor on the compressor. Inspect ampere with electrical tester. Test breaker switch using the same method. During hot summer weather when outdoor temperature is 100 F or more, it can overburden the machine and cause fuse to blow or breaker switch to turn off. If unit works after the above method, then there's no additional problem.
  2. Turn breaker switch off and repair where wire has burnt.
  3. Test for short or burnt control with electrical tester and then repair it
  4. Remove front of thermostat and connect R.Y.G. wire. Turn power switch on and if unit works then replace the thermostat.
  5. Disconnect power. Connect the power and turn switch on and then try running the unit.



B. Unit is running but warm air is coming out
Possible cause: (each cause has matching repair)
  1. Compressor not working
  2. Condenser fan motor is broken
  3. Dirty condenser
  4. Gas is leaking
  5. Electrical contactor on compressor is broken
  6. Defective thermostat
  7. In case of split-type of A/C, fuse or breaker switch for compressor is not working

Check and repair:
  1. Replace compressor
  2. Replace compressor fan motor. Check model to make sure voltage, RPM, rotation direction, HP, mounting, rotation shaft and bolt size are the same.
  3. Disconnect power and clean unit by spraying water with hose. Make sure motor or compressor doesn’t get wet and dry completely before operating.
  4. There is oil where gas is leaking. If leaking spot has flaring nut, tighten it more. Weld pipe where gas is leaking and vacuum completely. Add gas and operate.
  5. Replace with same model of electrical contactor.
  6. Follow problem A. # 4 solution.
  7. Follow problem A. # 1 solution.



C. Not enough cool air is coming out and interior room temperature is higher than before.
Possible cause: (each cause has matching repair)
  1. Dirty air filter
  2. Cooling coil is frozen
  3. Supply air duct has hole and air is leaking

Check and repair:
  1. Replace air filter
  2. If there’s insufficient gas, add more gas. Dirty air filter can cause coil to freeze so replace air filter. Operating on low outdoor temperature can cause coil to freeze. Make sure to thaw before operating again.
  3. Fix the leaking hole



D. Compressor is running but no air is coming out
Possible cause: (each cause has matching repair)
  1. Indoor air circulating blower motor is broken
  2. Faulty thermostat
  3. If split-type unit, power for furnace or air-handling unit has shut down

Check and repair:
  1. Check whether wire for blower motor has burnt, burning smell and defective bearing and replace blower motor.
  2. Remove front of thermostat and connect R.G. line. Turn power on and if motor runs, replace thermostat
  3. Check fuse and breaker switch and look for burnt wire



E. Some rooms are warm but other rooms are cool
Possible cause: (each cause has matching repair)
  1. Air supply duct is leaking
  2. Air supply duct is too narrow or too long

Check and repair:
  1. Repair leak
  2. Replace with larger duct or add new duct and install air supply register



F. There’s smoke or burning smell from the air coming out
Possible cause: (each cause has matching repair)
  1. Indoor blower motor is burnt

Check and repair:
  1. Stop operating immediately. Fan motor needs to be replaced. 10 ton or larger can use 3 phase motor so check for rotation direction. If rotation direction is different, switch 2 lines from 3 phase.



G. Fuse is blown and unit is not working
Possible cause: (each cause has matching repair)
  1. Fuse is blown and is burnt black and brown
  2. Fuse looks normal from outside view but is blown inside

Check and repair:
  1. If fuse is burnt black or brown, it has defective fuse or loose switch connection. Turn off power and repair or replace with new one
  2. If weather is hot over 95 F, high energy use can cause fuse to blow. Changing indoor thermostat too quickly and often can cause fuse to blow also. Turn off power and replace fuse. If unit operates normally after new fuse, there’s no additional problem. But if fuse blows again, there’s other problems and stop operating.



H. Breaker switch is off and compressor stopped
Possible cause: (each cause has matching repair)
  1. Electrical breaker switch is at Off position
  2. Breaker switch is between On and Off position
  3. Breaker switch is at On position

Check and repair:
Turn off indoor thermostat
  1. Move breaker switch to On position
  2. Move breaker switch to Off position. If it doesn’t move easily, push hard. Push hard to On position so it’s not in the middle position anymore. If it doesn’t solve problem, replace the switch
  3. Move breaker to Off position and then to On position. Repeat couple of times. Turn on thermostat. If breaker switch is turned On and becomes Off right away, there’s problem with machine or breaker switch and needs further examination.



I. Air conditioner is making lot of noise
Possible cause: (each cause has matching repair)
  1. Indoor air circulation blower has bad bearing
  2. Indoor air circulation blower’s motor has bad bearing
  3. Indoor air circulation blower’s blade has friction
  4. Condenser fan motor has bad bearing
  5. Condenser fan motor blade has friction
  6. Electrical contactor had bad contact
  7. Indoor air circulation blower’s belt is worn down
  8. Defective compressor

Check and repair:
  1. Replace
  2. Replace
  3. Check for motor and blower’s mount and tighten the bolt and nut. If defective, repair or replace
  4. Replace
  5. Check for motor and fan’s mount and tighten the bolt and nut. If defective, repair or replace
  6. Replace
  7. Replace
  8. Replace



J. Water leaks when air conditioner is running
Possible cause: (each cause has matching repair)
  1. Drain pipe is blocked
  2. Water collecting drain pan is worn and has hole

Check and repair:
  1. Clean inside the pipe with CO2 gas
  2. Repair drain pan or replace air conditioner



K. Compressor is hot and cannot be started
Possible cause: (each cause has matching repair)
  1. Compressor’s power terminal is burnt
  2. Defective running capacitor
  3. Defective electrical contactor
  4. Low voltage
  5. Changing the thermostat temperature too frequently in a short period of time

Check and repair:
  1. Replace with new terminal or replace compressor
  2. Replace with same capacity
  3. Replace
  4. Fix electrical problem to achieve normal voltage
  5. Don’t operate for a day and try running the unit next morning



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