Staying on top of your central air conditioner can save you big money on repair bills. Any number of small items can render your air conditioner inoperable. Before calling a repair service, troubleshoot some of the common air conditioning issues that cause a unit to fail. You can fix many of these items on your own, without the help of an HVAC professional. Check the Thermostat Check your thermostat to begin your central air conditioning troubleshooting. Make sure the thermostat switch is in the "on" position, and it's set to "cool." If the thermostat is a digital model, replace the batteries if applicable. Verify the temperature setting on the thermostat is lower than your room’s current temperature. Many times, thermostat settings cause the trouble. If the inside unit fails to come on once you've checked the thermostat setting, check the fan switch. The fan switch should be set to "auto" and not "off." If the switch is set to "auto," move the switch to the "on" position. If the fan does not come on, check the circuit breakers.

Replace the Air Filters Check the air filter inside your unit if it still doesn’t produce cool air. Pull out the filter and inspect both sides. If the filter appears dirty and clogged, you must replace it. You should clean or replace your air filter once a month to keep the unit working properly. A clogged air filter will cause the unit to work harder, overheat and not cool as efficiently. Check the Circuit Breakers Your air conditioning unit has two breakers; one operates the outside unit while the other operates the inside. If the breakers appear tripped, turn the breakers off and then back on to reset them. If the unit comes on briefly once you reset the breakers, but they trip once again, call an air conditioning service provider to check the electrical wiring. Check the Condensate Drain If resetting the breakers turns the unit back on, but the unit still won’t cool, check the condensate drain line. A float-switch safety device sits inside the drain. Should the line clog, the float-switch turns off the unit.

This stops the creation of condensate that could overflow, damaging the unit and your home. Attach a wet/dry vacuum to the condensate drain line outside your home to ensure it is free from clogs. Check the condensate drain line inside your home while running the vacuum. You should hear air rushing through the line. This means the vacuum has removed all excess water and gunk built up inside the drain. Once you've completed the inside central air conditioning troubleshooting, check the outside unit. Check the Outside Safety Disconnect If the inside unit is operating, but the outside unit is not, check the disconnect switch on the exterior wall. This separate safety shut-off switch allows an air conditioning service provider to interrupt the power to the unit when making repairs. If the disconnect switch is in the "off" position, turn it on to see if the outside unit starts. If it doesn't start, check the switch fuses. Test the fuses with a continuity tester if you feel comfortable working with electricity;

if not, you may need to call a professional. If the fuses are good, and the disconnect switch is in the "on" position, it may be the dual capacitor or the fan motor. Check the Outside Unit The outside unit requires both the fan motor and a dual capacitor to operate the condenser. used ac window unit for saleIf the fan isn't turning, but you can hear the condenser, have your fan motor replaced as this puts too much strain on the condenser. how much does a central ac unit cost to replaceIf the fan motor isn't running and you cannot hear the condenser, have a professional check the dual capacitor, as it may need replacing. how to repair my ac unitReferences InspectAPedia: Air Conditioning Diagnosis, & Repair GuideCarrier: Troubleshooting GuideYork: Air Conditioner Troubleshooting GuideDon Vandervort’s Home Tips: Air Conditioners – Central Photo Credits Jupiterimages/liquidlibrary/Getty Images Suggest a Correction

Imagine your body is wrapped in a fuzzy, wool blanket on a sizzling summer day. The wool blanket prevents heat in your body from escaping, causing your body to overheat.But your air conditioner goes through this same struggle every year when it gets covered in leaves, dust and dirt. And it’s costing you money.Look at the outside unit on the left of this image from AHRI. Its job is to release heat the refrigerant absorbed from your indoor air.But if the outside unit’s condenser coils (what the refrigerant flows through) are covered in dirt, it can’t release the heat. Just like how your body couldn’t release the heat when wrapped in the wool blanket.So the air conditioner needs to run longer to cool your home. You spend more money. And the air conditioner risks overheating—leading to a breakdown on the hottest day of the year.So here’s how to prevent all that by cleaning the outside unit.Do this at least once a year, preferably during spring.Cleaning the air conditioner’s outside unit is just one of many tasks that need to be done to maintain your system’s energy efficiency.

Check out our maintenance checklist to see everything we do during a maintenance visit. This includes cleaning your outside unit, if you don’t have the time to do it yourself.Schedule a $88 air conditioner tune-up today.Did you find this article helpful? Sign up for our newsletter to get home how-to’s, money-saving tips and specials sent straight to your inbox.Service Champions, your local heating and air conditioning company, serves San Jose, Sacramento, East Bay and the surrounding areas. For more information on any of our HVAC products or services, contact us online.Your Heating & Air Conditioning Contractor How Comfortable Do You Want To Be? You Have Problems, We Have Answers Commonly Reported HVAC Problems: Copyright © 1997 Hannabery HVAC. Outdoor unit won't shut off unless I use the circuit breaker:The thermostat reaches the desired temperature, the indoor unit shuts off, the air stops blowing, but the outdoor unit keeps on running. In the heating mode (if it's a heat pump) it could eventually shut off on a high pressure safety device.

But in the cooling mode, it could run forever unless you turn the breaker off. And this will cause the indoor coil to freeze up into a solid block of ice, eventually the ice will build-up and travel all the way to the outdoor unit. So what causes this? Only a few things, the most common of which is a stuck compressor contactor - located in the outdoor unit. The contacts tend to get pitted-up. Eventually they can weld shut. This can cause serious damage to the system. It is good practice to replace the contactor every few years or when pitted - just like spark plugs in a car. Another cause would be a shorted thermostat cable. This can be caused by a weed-whacker hitting the wire outside, or a wire-staple digging into the wire too tightly, rodents chewing on it, or just bad wire. Lastly, the thermostat itself could be bad, sending a signal to the outdoor unit when it isn't supposed to. Below is a list of possible causes. Items in red usually require a service call. Items in blue however can be addressed, some even fixed by the homeowner.