Diagnosing a Central Air Conditioner Unit

Are you facing problems with your central air-conditioning unit? Most often, the problems are caused by trivial reasons. These simple tips will help you to identify and solve the problems.

Diagnosing problems

A minor problem with any of the air-conditioning components can affect the entire device. Following is a malfunction list comprising of the possible problems with your central air-conditioning unit.  

Cooling related problems

This is the most common problem with a central air-conditioning unit. This problem may persist despite the fact that the unit turns on without any difficulty. Follow these steps to solve the problem.

  • Switch off the main power
  • Turn off the 240-volt current which is situated on the main electrical panel
  • Trim off any sort of vegetation that is obstructing the unit
  • Remove the protective grille
  • Clean the fins using a soft brush
  • Use a vacuum cleaner to remove any obstinate particles
  • Detach the top grille of the unit
  • Use an air-hose to clean the fins
  • Lubricate the motor with oil and reattach the unit
  • Test the unit by switching the power on

Air conditioner does not turn on

Follow these simple steps if your air-conditioning device does not turn on automatically.

  • Ensure the thermostat is put to cool, below the current temperature
  • Check the electrical panel for a blown fuse or tripped breaker
  • Check if the furnace power is switched on
  • Turn off the main power and check the thermostat
  • Take out the cover of the thermostat. Unscrew the wire from the ‘Y’ terminal. Turn the power back on and hold the ‘R’ terminal in your hand.
  • Touch the insulated part while doing this. Replace the thermostat if the compressor gives a sudden jerk.

Evaporator Coils

The evaporator coils will not perform efficiently if there is a frost build-up. Switch off the air conditioner when you identify a frost build-up.


The compressor can switch off unexpectedly when it exceeds the high-pressure limit. Solve this problem by pushing the reset button on the compressor’s panel. 

Room Temperature

Many times, the room temperature can go below the actual selected temperature. This problem can occur if the thermostat is not installed properly.

Air Handler

Strange squealing noises coming from the air handler is a common occurrence. The problem arises when the connector belt, which holds the motor to the fan, gets displaced from its position. Replace the belt if it is worn out. To replace it, you will have to detach the access panel and realign the belt. Do not over-tighten it, as it can affect the motor bearings.

Noisy ducts

To solve the problem of noisy ducts, you will have to insert a flexible insulation between   the cooling system and the ductwork runs.

Water pools

It is common for water pools to form next to your air conditioner. Fix this problem by checking the drain tubes for any sort of leakages. Examine the tube for blockages like algae. Pour a solution of bleach to remove the algae.