There are many possible causes for poor air-conditioning performance and failures; many of them - in the case of central AC systems - are due to poor installation and inadequate sizing, or to poor maintenance. Many people assume that air conditioners do not need regular maintenance; but nothing could be further from the reality.
Regular maintenance and cleaning is crucial, namely for central systems.
CAUSES OF MALFUNCTION
Many people assume wrongly that air conditioners do not need regular maintenance. Improper installation and sizing (mainly in central AC systems) are a cause of problems (blasts and temperature swings, failure, wear).
Before calling a professional AC…
- … check the thermostat. See if it is set in the "Cool" position.
- … check the outdoor air conditioning (condensing unit). See if the circuit breakers are "On".
- … check the "disconnect switch" of the outdoor unit. Is it in the "On" position?
- … check the blower motor in your furnace. Is it running? If the thermostat is in the "Cool" position, it should be running.
- … check the return air grilles. See if they are unblocked.
- … check the supply air registers. Are they open and blowing air? Aren't they blocked by furniture?
- … look for open or leaky windows and doors; they interact with the functioning of air conditioners.
Looking for causes of AC failures
Many AC problems have their ultimate cause in a poor installation, in wire corrosion or in electrical connections damaged by overuse and strain... But poor maintenance, dirty filters, or buttons in the wrong position are also common sources of many AC failures.
Filters: blocked filters are a common cause of poor performance and failures; they cause slow airflow, which in turn can block the system…
Fuses and circuit breakers: check them; before resetting the breakers, let the unit cool down for some few minutes.
Compressors malfunction: check the high-pressure limit switch, and reset it by pushing the button.
Electric control failure: electrical connections and contacts may be damaged by overuse and strain; or by an oversized system.
Sensors: if your room air conditioner is cycling constantly and behaving erratically, inspect the thermostat sensor. Is it well positioned?
Drainage: check the condensate drain. See if it isn't clogged; see if it is draining properly (room air conditioners).