DIY Do It Yourself Air Conditioning Repair Help
On a Central Air Conditioning Unit : Common Questions
Is the wall thermostat set to Air Conditioning? Is the fan setting on Auto? If Yes
Is either of the units running? The inside unit (air handler)? The outside unit (the condenser)?
If the air handler is not running. Is the Blower Cover in place depressing the cover safety switch?
When accessing the electrical compartment of the air handler: Does the air handler have a air handler control board with a LED that flashes to show what the error is? If so count the number of flashes and compare that number with the legend on the wiring schematic.
If the air handler does not have a air handler control board: Find the fan relay, you will need a multimeter to find if the fan relay has 24 volts going to the fan relay coil,be sure the cover panel safety switch is depressed. 24 volts Y/N? If Yes is the fan motor relay supplying power to the air handler fan motor? If Yes the problem may be the air handler fan motor or the motor run capacitor.
If No If the energized fan motor relay is not supplying power to the air handler fan motor you may need to replace the fan motor relay.
If the inside air handler is running properly: Is the Condensing Unit Outside Running? Yes
If so, is the compressor running? If so, is the small copper tube leaving the outside condenser unit warmer that the larger copper tube? If the small tube is very hot then the condenser coils may need cleaning. Disconnect the power supply going to the outside condenser unit. Using a garden hose, with the power supply interrupted, spray water straight through the coil fins to clean the dust and dirt from them.Be sure to spray the water parallel to the fins so that they do not become bent or damaged. When finish wait 15-30 minutes then turn on the power supply to the outside condenser unit. After 15 minutes of running, is the inside air handler circulating cooler air than before? Normally a 15-20 degree temperature difference will be attained between the inside air handler intake and the inside air handler exhaust.
If the inside air handler is running properly: Is the Condensing Unit Outside Running? No
Disconnect the High Voltage Supply to the outside condensening unit. Remove the cover on the outside condensening unit electrical compartment.
Is the Power Contactor inside the outside condenser unit electrical compartment Energized? No
Is the Low Voltage Power Supply providing the minimum low voltage requirement to the Power Contactor? If Yes, you may need to replace the condensing unit power contactor. If the low voltage is not present? Then follow the low voltage wiring back to the low voltage transformer inside the air handler,checking for breaks in the wire. If the low voltage transformer has line voltage entering the low voltage transformer primary but no low voltage is coming out of the secondary transformer side: replace the low voltage transformer.
Is the minimum line voltage requirement coming through the Power Contactor? Yes
Is there the same voltage at the Power Contactor input as the output?
If Yes and neither the condensing fan motor or the compressor is running the problem may be in the condensing unit dual run capacitor.