Tip & How-To about Heating & Cooling
Most problems with air conditioners (A/C) are electrical problems, not Freon problems. This is an article containing tips on troubleshooting A/C electrical problems.There are two circuits involved in an air conditioner. There is the line voltage, 120 or 240 Volts Alternating Current (VAC) and the control voltage (24VAC) circuits. The control voltage is used to turn on the line voltage compressor and motors.
In troubleshooting A/C problems you have to determine if the problem is a control circuitry issue or a line voltage issue or component.The first thing you want to do is determine if you have line voltage. You check the breaker at your main fuse box and any fuses at the disconnect box next to the outdoor unit. To check the fuses, turn the power off at the breaker box and remove the fuses. Take a multimeter and place it on the resistance setting. (Rx1) Place one lead on one end of the fuse and the other lead on the opposite end. If the meter arrow goes to zero, the fuse is good. If it stays at infinity (a sign that looks like an 8) it is bad or open. Replace the fuse, as they will blow especially during initial season start-up of the compressor.
If you take your thermostat cover off you will see several small wires. If you take a jumper wire and touch the red wire to the green wire the indoor fan motor should start. This tells you that you have 24VAC control voltage. If it doesn't start, there is a transformer or control voltage wiring problem.To further confirm you have a control voltage problem, remove the access panel to the outdoor unit. You will see a contactor. Use an insulated screwdriver and manually push that contactor in. (Make sure your hand is on the insulated portion of the screwdriver) If the outdoor fan and compressor start, the problem is in the 24VAC control circuitry.
Check for input line voltage at the transformer with a multimeter set on 120 or 240VAC. If you have line voltage, check the output side of the transformer for 24VAC. Trace the problem from the location you have voltage to the place you do not, but should have, using the wire diagram or common sense.
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