Central Air Conditioner Doesnít Operate At All

If your central hvac doesnít go on automatically when the thermostat signals the need for cooling, itís most probably that the thermostat isnít working correctly or the device is receiving electrical power. Before you do anything else, make sure the thermostat is set to COOL and its temperature setting is well below the ambient temperature.
Then perform the following:

1 Examine the main electrical panel as well as any secondary circuit panels for a tripped breaker or blown fuse. If you discover the issue there, reset the circuit breaker by switching it off and then on or replace the fuse. A central hvac must be on a dedicated 240-volt circuit.

2 Make sure the air conditioner on / off switch is turned on and that the outdoor condenserís on / off switch, that is mounted on the outdoor unit, hasnít been turn off. Also be sure the 240-volt disconnect near the compressor, which happens to be in a metal box usually mounted on the house wall, hasnít been shut off.

3 Turn off the power to the hvac and check the thermostat. Take off the thermostatís cover from the bottom (usually by yanking straight out) and replace the batteries (if it has batteries). Replace the cover and wait around three or four minutes and then try the system again.

4 If that doesnít do the job, open the thermostat again and unscrew the wire from the Y terminal. Turn the power back on. Holding the wire by its insulation only, touch the bare end to the R terminal and hold it there for about two minutes. If the compressor kicks on, the thermostat is defective; replace it. If the compressor doesnít go on whenever you hold the two wires together, turn the power back off and phone an air-conditioning expert.

Still not working? Please keep reading.

Air Conditioner Doesnít Cool Well

If you can hear your central air conditioner working, but it doesnít cool well, the problem might be caused by a couple of issues. The very first thing to perform is make sure the filter in the air handler is clear so that it receives proper air flow.

1 Turn off the power to the ac unit.

2 Take out the door on the front of the air-handler cabinet to give you accessibility to the filter. Grab the filter and clean or change it out as necessary.

3 Look for ice. If you see ice in the area around the coils, close the device back up, turn the power back on, and turn on the fan. The ice should dissolve within an hour or two.

4 Clear the condensate drain. Ac units can create a lot of water simply because they remove moisture from the air. To remove this, they have a [usually plastic] drain pipe that comes out from the side of the air handler. Over time, algae can block this water pipe and, when it does, the A/C wonít work. Water is also likely to puddle near the unit or perhaps flood the area. 

5 Clean the outdoor compressor. 

6 Make sure the compressor is working. When you set the thermostat to a temperature below the room temperature, you should notice the outdoor compressor run and see the fan turning inside the top. If the fan isnít rotating, try to find an overload button or switch to reset (not all types have this). Stick a screwdriver down through the top grille and then try to spin the fan blades clockwise. They should spin freely. If doing this gives the fan enough of a boost to get going, the system has a faulty capacitor that must be replaced by an Air conditioning repair technician.

If none of these tips worked, the likelihood is pretty good that the coolant needs to be recharged by an air conditioning professional.

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