How Does a Central AC System Work?
In order to better understand what may cause your AC to not work properly and blow cold air, it will help to know how it works.
Your air conditioning unit uses a liquid refrigerant. This liquid passes over the indoor evaporator coils to absorb the heat inside your home. Absorbing the heat transforms this liquid into an icy gas. The AC unit’s fan blows across those refrigerant-cooled coils and pushes cold air through the duct work out to circulate into the home.
The gas-form of the refrigerant carries the heat back to the outdoor condensing unit where it transforms into a liquid after releasing the heat to the outdoor air.
Causes Of Air Conditioner Not Blowing Cold Air
Thermostat issues
If all looks good on the power front and your AC is still not blowing cold air, it could be that the thermostat on your unit isn’t set at an appropriate temperature. Try turning the dial down all the way, or pushing the buttons to the lowest setting and see if that trips the unit to run. If you’re able to, check to ensure all wiring into the thermostat unit (and any batteries, if applicable) are connected properly.
Clogged Drain Causing Water Buildup And Shutting Down Compressor
Every air conditioner also works as a dehumidifier. Bigger 3+ ton AC units can remove more than 100 pints of air moisture from your indoor air. All that water has to go somewhere.
That’s why air conditioners have drainage systems. The collected water is drained via a hose or a pipe. If the drain is clogged, the air conditioner will accumulate water. In essence, it will be “flooded”.
When that happens, the AC compressor – the very part responsible for achieving the cooling effect in the cooling coils – might shut down. Mind you, the fan might be working just fine. The net result will be the AC unit running but not cooling.
Fortunately, it’s quite easy to fix a clogged AC drain. You just unclog it.
Power Issue
It’s possible that the initial power surge tripped the breaker or blew a fuse. Try resetting your breaker and turning on the AC again to see if that solves the problem. You may also check to see whether there is an overload switch built into the motor. Finally, check the power cable to ensure it hasn’t been pulled out of the socket.