Tip & How-To about Heating & Cooling

Troubleshooting Air Conditioner Electrical Problems

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.



.

Posted by on

Heating & Cooling Logo

Related Topics:

Related Questions:

1 Answer

the evaporator full of ice?


Hi,
Either low air flow or low freon charge...
Here is a tip about troubleshooting your air conditioner...
There are many things that can cause your air conditioner not to cool...

AirConditioner Trouble - Review the Possibilities

heatman101

Sep 05, 2011 | Haier HWR08XC7 Air Conditioner

2 Answers

Frigidaire FAH125N2T Air Conditioner is 6 years and still runs very smooth but no longer blows cold air. What could be the problem?


Hi,

Here is a tip about troubleshooting your air conditioner...
There are many things that can cause your air conditioner not to cool…

Air Conditioner Trouble - Review the Possibilities

heatman101

Sep 04, 2010 | Frigidaire FAH125N2T Air Conditioner

1 Answer

my air contioner runs but not cold, do you think i need to add coolant ? and if so what kind do i add ?


Hi,
You may need freon, but don't attempt it yourself...

How to add Freon to a Air Conditioner or Refrigeration System
http://www.fixya.com/support/r5638346-add_freon_air_conditioner_or

Here is a tip about troubleshooting your air conditioner...
There are many things that can cause your air conditioner not to cool…

Air Conditioner Trouble -Review the Possibilities
http://www.fixya.com/support/r3571569-air_conditioner_trouble_review_the_possi

heatman101

Aug 21, 2010 | Coleman Mach 15 Air Conditioner

1 Answer

Return fins on front of unit (behind air fliter) continue to freeze up.


Hi,
You may need freon, but don't attempt it yourself...

How to add Freon to a Air Conditioner or Refrigeration System
http://www.fixya.com/support/r5638346-add_freon_air_conditioner_or

Here is a tip about troubleshooting your air conditioner...
There are many things that can cause your air conditioner not to cool…

Air Conditioner Trouble -Review the Possibilities
http://www.fixya.com/support/r3571569-air_conditioner_trouble_review_the_possi

heatman101

Aug 21, 2010 | Whirlpool CA24WCR Thru-Wall/Window Air...

Not finding what you are looking for?

3,554 people viewed this tip

Ask a Question

Usually answered in minutes!

Top Heating & Cooling Experts

paulcarew

Level 3 Expert

2458 Answers

Dan Webster
Dan Webster

Level 3 Expert

8220 Answers

Donni Steen

Level 3 Expert

659 Answers

Are you a Heating and Cooling Expert? Answer questions, earn points and help others

Answer questions

Loading...