The first and most basic action to take to prolong your ac units life is to replace the filter. You should replace it whenever it gets filthy. Depending upon the use, that can range from every three to six months. There are some filters out there which can last up to a year. Ask someone in the hardware shop for more suggestions.
Once a year, make certain that you check the evaporator coil located inside the air handler to ensure there is no dust build up. When the weather starts to cool, you should check the outside of the air conditioning unit. You should check around the unit and ensure there is no debris on the surface of the condenser, as that will stop air flow. Also, you should check in between the fins of the condenser to see that its not plugged with dead insects or pollen. Spraying the condenser with a hose will typically be good enough to get rid of all the debris.
Although lots of air conditioners today make use of direct drive motors, it is a good idea to check the belt in the air handler. You might have to replace it. If no change is needed, you might only have to oil the motor bearings once a year.
It is also good to check the contactors and other electrical parts; many of them are located inside the condensing unit. The contactor operates the compressor, and the contacts get pitted and need to be replaced occasionally. Various manufacturers use different types of contactors, so check the manual to discover exactly what kind you need Visit this link .