Air Conditioner Problem
Problem / Symptoms:
- Unit is not running
- Unit is running but warm air is coming out
- Not enough cool air is coming out and interior room temperature is higher than before
- Compressor is running but no air is coming out
- Some rooms are warm but other rooms are cool
- There’s smoke or burning smell from the air coming out
- Fuse is blown and unit is not working
- Electric circuit breaker switch is off and compressor stopped
- Air conditioner is making lot of noise
- Water leaks when air conditioner is running
- Compressor is hot and cannot be started
A. Unit is not runningPossible cause: (each cause has matching repair)
- Fuse has blown or breaker switch is off
- Electrical wire burned
- 24 volt transformer burned or 24 volt fuse blown
- Defective thermostat
- In case of high pressure control, reset switch is turned
- 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.
- Turn breaker switch off and repair where wire has burnt.
- Test for short or burnt control with electrical tester and then repair it
- Remove front of thermostat and connect R.Y.G. wire. Turn power switch on and if unit works then replace the thermostat.
- Disconnect power. Connect the power and turn switch on and
then try running the unit.
B. Unit is running but warm air is coming outPossible cause: (each cause has matching repair)
- Compressor not working
- Condenser fan motor is broken
- Dirty condenser
- Gas is leaking
- Electrical contactor on compressor is broken
- Defective thermostat
- In case of split-type of A/C, fuse or breaker switch for
compressor is not working
- Replace compressor
- Replace compressor fan motor. Check model to make sure voltage, RPM, rotation direction, HP, mounting, rotation shaft and bolt size are the same.
- Disconnect power and clean unit by spraying water with hose. Make sure motor or compressor doesn’t get wet and dry completely before operating.
- 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.
- Replace with same model of electrical contactor.
- Follow problem A. # 4 solution.
- 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)
- Dirty air filter
- Cooling coil is frozen
- Supply air duct has hole and air is leaking
- Replace air filter
- 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.
- Fix the leaking hole
D. Compressor is running but no air is coming outPossible cause: (each cause has matching repair)
- Indoor air circulating blower motor is broken
- Faulty thermostat
- If split-type unit, power for furnace or air-handling unit
has shut down
- Check whether wire for blower motor has burnt, burning smell and defective bearing and replace blower motor.
- Remove front of thermostat and connect R.G. line. Turn power on and if motor runs, replace thermostat
- Check fuse and breaker switch and look for burnt wire
E. Some rooms are warm but other rooms are coolPossible cause: (each cause has matching repair)
- Air supply duct is leaking
- Air supply duct is too narrow or too long
- Repair leak
- Replace with larger duct or add new duct and install air
F. There’s smoke or burning smell from the air coming outPossible cause: (each cause has matching repair)
- Indoor blower motor is burnt
- 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 workingPossible cause: (each cause has matching repair)
- Fuse is blown and is burnt black and brown
- Fuse looks normal from outside view but is blown inside
- 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
- 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 stoppedPossible cause: (each cause has matching repair)
- Electrical breaker switch is at Off position
- Breaker switch is between On and Off position
- Breaker switch is at On position
Turn off indoor thermostat
- Move breaker switch to On position
- 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
- 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 noisePossible cause: (each cause has matching repair)
- Indoor air circulation blower has bad bearing
- Indoor air circulation blower’s motor has bad bearing
- Indoor air circulation blower’s blade has friction
- Condenser fan motor has bad bearing
- Condenser fan motor blade has friction
- Electrical contactor had bad contact
- Indoor air circulation blower’s belt is worn down
- Defective compressor
- Check for motor and blower’s mount and tighten the bolt and nut. If defective, repair or replace
- Check for motor and fan’s mount and tighten the bolt and nut. If defective, repair or replace
J. Water leaks when air conditioner is runningPossible cause: (each cause has matching repair)
- Drain pipe is blocked
- Water collecting drain pan is worn and has hole
- Clean inside the pipe with CO2 gas
- Repair drain pan or replace air conditioner
K. Compressor is hot and cannot be startedPossible cause: (each cause has matching repair)
- Compressor’s power terminal is burnt
- Defective running capacitor
- Defective electrical contactor
- Low voltage
- Changing the thermostat temperature too frequently in a short period of time
- Replace with new terminal or replace compressor
- Replace with same capacity
- Fix electrical problem to achieve normal voltage
- Don’t operate for a day and try running the unit next