How to test your central air system before calling out a technician

It can happen to any of us. One sunny afternoon when the heat gets increasingly unbearable and you have rushed home to be in comfort of your air conditioner, you suddenly notice that your air conditioner is not working as it should. It is not adjusting the temperature of the room the way it used to.

Before you call in the contractor for an  inspection you can actually do a bit of testing by yourself to see if everything is alright. This will not only save you quite a few bucks but would also save you time. However, if you do find the problem to be too complicated for you to deal with you should of course call an expert air conditioner contractor to inspect your unit.

To test your central air conditioner, you must have the outside temperature above 60 degree Fahrenheit for a period of two days or 48 hours to be precise. Some manufacturers may even recommend a temperature of 65 degrees. This is because turning on the air conditioner at a temperature lower than 60 degrees might actually damage the compressor of the unit.

Next you turn the regulator of the fan to 'auto'. The thermostat level should also be adjusted at a temperature below the normal room temperature. It is recommended to set it somewhere around 76 degrees to 78 degrees Fahrenheit. This would make the fan and condensing unit to switch on immediately. However, if there is a preset time delay it would take that time to turn on.

After letting the system run for 8 to 10 minutes so that the temperature in the ductwork is balanced you need to check the temperature at the supply and return registers of the unit. If everything is fine the temperature reading at the supply register would be 14 to 20 degrees cooler than the return ducts.

If the difference in temperature is more than 20 degrees then it would indicate that air is restricted. This can be because of three reasons:

- An unclean filter
- Improper ductwork
- Problem with the fan as in it is not of proper size or moving too slowly.

If the temperature difference is less than 14 degrees then the possible causes for problems are:

- Loss of refrigerant
- Unclean coil
- A compressor not working quite up to the mark
- A fan that is much larger for the unit
- An improper return air system.