Air Conditioner Trouble Shooting Tips!

Air conditioner trouble shooting and repair guides: The following guides are only to be followed if it is understood that the power is turned “OFF” completely. “Failure to do so may cause severe electrical shock, or even death.”

The following are the most common problems which may arise from an airconditioner. They are:

Circuit Breakers

1) Unit will not run – After switching “on”, there was no movement, no sound.

a) Check for defective fuse or circuit breaker. Adjust the Ohmmeter selector to “resistance”, set dial to x1K. Check for continuity on the fuse and on the circuit breaker. Replace if defective.


b) Selector switch might be defective. Remove and check visually for burn wires or contacts. Measure for continuity. Replace if defective.

c) Low line voltage.

Aircon Filter

2) Unit is not cooling correctly – Fan and compressor are running, but only warm air is coming out.

a) Very dirty filter. Remove, clean and return to housing.

b) Lack of refrigerant. Charge refrigerant. We will discuss this in another page.

c) Defective filter/dryer. Replace it with a new one.

Filter Dryer

d) Defective condenser. Disconnect it and flush with R-11 until it is completely clean. Reconnect the coils.

e) Defective compressor. Different test must be made to find out what is wrong with the compressor. At any rate, if the compressor is defective, replace it with a new one. We will discuss this subject in depth on the next page.

3) Compressor runs “on” and “off.” – Air


conditioner is running but the compressor sometimes run and sometimes stop.

a) High ampere reading on the compressor – use a clamp-meter, clamp one of the two wires going to the compressor. The “RA” (running current) reading should be within the manufacturer’s specification. If not, the compressor should undergo further test.


b) Very dirty condenser – condenser coils are covered with dust and dirt, air cannot absorb the heat released by condenser. Clean condenser thoroughly.

4) When switched "on", only the fan motor is running – When switch is positioned in “low”, “medium” or “high”, the fan is running, but the compressor will not run.

a) Defective wiring – check electrical wiring connections. Look for loose or disconnection.

Overload Protector

b) Low voltage.

c) Defective thermostat – Turn the thermostat to the coldest setting, if the motor is not running and the room temperature is 75 degrees Fahrenheit, replace the thermostat.

d) Defective capacitor – Check starting capacitor and run capacitor. If it is


defective, replace with a new one.

e) Defective fan motor – Touch fan motor, if it is abnormally hot, check the winding resistance. Repair or replace fan motor if necessary.

5) Evaporator is covered with ice – Poor cooling in all fan speed.

Fan Motor

a) Dirty filter/dryer. Replace with new one. But doing so you must re-process the system to rid of moisture and dirt.

b) Lack of refrigerant. Recharge refrigerant. If your unit does not have a service valve, install a "bullet piercing valve" and charge required refrigerant volume.

c) Faulty fan motor. Check fan motor if it is abnormally

Filter Dryer

hot, repair or replace.

6) Air conditioner Vibrates, rattles, or hums – During operation, you can hear audible rattling sounds or hums.

a) Loose compressor foundation bolts. Tighten loose bolts.

b) Copper tubing striking metal surface. Tie copper tube to a nearby large tube with plastic tie-wrap.

Fan Blades

c) Loose fan blade. Tighten.

d) Fan motor not aligned properly. Re-align fan motor.

e) Unit not properly installed. Install it properly.

f) Wrong value capacitor. Replace immediately.

7) Water is dripping into the room.During operation, water is dripping on the floor.

a) Unit is not leveled correctly. Check level. Unit must tip slightly downward on the outside.

b) Condenser fan "slinger" is broken. Replace with a new fan.

c) Base pan rusty and have holes. Have it repaired and painted.

d) Base pan drain hole clogged. Remove clog.

An air conditioner will serve you well into many years if you provide it with a scheduled preventive maintenance. If problem arise try following the trouble shooting tips above!

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