What to Check First if the Air Conditioner Output is Inadequate or A/C Won't Run

A quick and easy A/C diagnostic guide

Has your A/C quit running?  Here are a few things you can try before scheduling a service call.   It is very possible you can get cool air pushing through the vents within seconds and save money!  Naturally, if you do not feel safe following these tips or are unsure of how to go about this then please schedule an appointment.

Air Conditioning Checklist for Lost Cooling: What to Do First

1. Adjust the thermostat setting to at least 5 degrees cooler.  Wait about 3 minutes.  The A/C may come on directly after doing so.
2. Check that the Thermostat is set to "Cool" Make sure the Thermostat is set to "Cool" otherwise it will never turn the A/C on.  Other settings it can be on may be "Heat" or "Off"
3. Check that the power is on for the A/C. You should check that the service switches are powered on.  Places to look are in the "furnace room" by the air handler, outside by the compressor(out door unit), and check the the fuses or circuit breakers at the control panel.
4. Check the Compressor(outdoor unit): Is it's fan running? running? If not, be sure that the outdoor service switch and the indoor power switch, fuse, or circuit breaker are all in the "on" position.
5. Check the Indoor Air Handler: is the indoor blower unit running? If not be sure that the electrical power switch at your furnace or air conditioner air-handler is in the "on" position. Sometimes there is more than one switch, such as one right at the unit and another at the entry to the room where the equipment is located, or even upstairs on a higher floor if your air handler is in a basement or crawl space.
6. Check the air filter(s): if your air conditioning equipment is running but little or no cool air is coming out of the supply registers, make sure your filters are not clogged.  If you regularly change your filters then this problem should not occur.  Usually the air filter is right at the air handler or blower unit(at the furnace), or your air filter may be installed behind a grille covering a central warm-air return that sends air back to the air handler.
7. Check the vents: in ceilings, walls, or floors, where cool air is supposed to be delivered to various rooms in the building, be sure that the register is in the "open" position (you will be able to see through it into the ductwork) and be sure you haven't blocked the supply registers with carpet, furniture, or clutter.