Before you make that call, try this basic air conditioner troubleshooting guide. This guide will help you to diagnose problems with your typical ducted split type air conditioner. A typical repairman will cost you about one hundred dollars per hour. With a few household tools and a little bit of knowledge, you can do it yourself and save that money. (You provide the tools and we will help with the knowledge part.)You should ensure that the routine maintenance has been performed on the unit. If the air filter has not been changed in the past month, check to see if it is dirty. **NOTE** ONLY YOU CAN ASSESS YOUR ABILITY TO PERFORM THIS TASK. THIS IS A GUIDE AND CANNOT PROVIDE ALL OF THE DETAILS FOR EVERY SITUATION. Begin your air conditioner troubleshooting at the thermostat by ensuring that the thermostat is on cool and that it is set lower than actual room temperature. This is to ensure that there really is a problem. It may seem silly but that is the first thing a repairman will check and you will normally still be charged a service call even if that is the only problem.

If there is not, then, check to see if the fan on the outside unit is running. If the fan on the outside unit is not running either, check to make sure that the breakers for the furnace/air handler and the air conditioner are on. Air Handling Unit Bag FiltersIf the breaker is not tripped, then the problem may be your thermostat, the furnace/air handler control board, or the wires between the furnace/air handler and the thermostat.42 Bathroom Vanity With Granite Top If your unit has a condensate pump, check to make sure the reservoir is not full. Vacuum Cleaner Fan AssemblyIf the reservoir is full, a limit switch will normally stop the air conditioner from running. You will need to repair or replace the pump.If the breaker is tripped, you can reset it by shutting it off and then turning it back on.

If it trips again, then check the wiring in the furnace/air handler for signs of damage and repair as necessary.If the blower is running but the fan on the outside unit is not, then continue your air conditioner troubleshooting at the outside unit. If the blower isn't running but the fan outside is, the problem could be the blower motor, it's run capacitor, or the furnace/air handler control board.If the fan motor is not running, then shut the power off to the unit. Then check all wire connections for signs of damage such as burning and repair as necessary. You should also check the wire connections in the compressor terminal box and repair if necessary. You can use our capacitor testing guide to check the unit's capacitors and replace as necessary.Continue your air conditioner troubleshooting by turning the power back on to the unit and observe whether the contactor closes or not. If the unit does not start, look for a reset button. Some units have a high pressure cutout switch that can be reset.

Then, use a voltmeter to check to see if you have power to the unit and 24 vac to the contactor's coil. If you do not have power to the unit, you should check the wiring between the electric panel and the unit. If you do not have 24 volts to the contactor's coil, check the thermostat and the low voltage wires from the furnace/air handler to the condensing unit. If you have power to the unit and the coil on the contactor but the unit does not start, the unit's contactor may be bad.If the compressor starts but the fan does not, the condenser fan motor could be the problem.If the condenser fan starts but the compressor does not, the unit may be low on refrigerant, the compressor might be too hot, or the compressor might be bad. If the blower on the furnace is running, check to see if you see any frost or ice around the units. You might also notice water around the furnace. Is there ice on the copper lines going outside? If yes, then shut the outside unit off for a couple of hours but let the blower on the furnace run.

This will allow the ice to melt. After two hours, you can continue your air conditioner troubleshooting. Turn the ac back on and let it run for about five minutes. Now feel the larger copper line at the outdoor unit. This should be cold and have condensation on it. If it is not cold or if frost is forming on the line, it is probably a freon problem. You will need to call a repairman because of federal refrigerant usage regulations.If there is no ice or frost, then continue troubleshooting at the outside unit. If the condenser fan and the compressor both run but the cooling effect is not adequate, you should check the temperature drop of the system. To measure the temperature drop, measure the air temperature leaving the air handler and subtract it from the temperature of the air entering the air handler. The result should be about 15 degrees for a high efficiency unit and about 18 to 20 degrees for an older unit (SEER less than 10). If the temperature drop is significantly lower than that, the problem may be the refrigerant charge.

If the temperature drop is significantly higher than that, then your air conditioner troubleshooting should focus on the system's air flow. The evaporator coil, filter, or blower wheel could be dirty. This is usually the result of not performing routine maintenance on the system. It could also be caused by a duct system that is too small. This is usually the result of improper design or installation. You may be able to increase the blower's cooling speed or replace your existing blower motor with a variable speed motor to overcome that problem. Now, you can get live support or leave a message for the HVACrepairguy through Facebook Messenger.Our experts shows you easy DIY solutions for the most common central air conditioning repairs. You'll be up and running sooner and will save the expense of a service call. Overview: Central air conditioner failures and solutions When a central A/C unit fails during a heat spell, you may have to wait days for a technician to show up, and you'll probably pay at least several hundred for the repair.

But if you're comfortable and are willing to spend about $50 on parts, you can probably repair you air conditioner yourself in about two hours and save about $225 on parts We talked to local HVAC technicians to get their best do-it-yourself A/C repair and help you with the most common “low cooling” and need an inexpensive multimeter, a voltage sniffer, an and a socket set. If these fixes don't work, at least you've covered the most common failures, and your service guy can concentrate on finding the more elusive problem. the new parts, you'll likely add years of Make sure the problem isn't the furnace Set your thermostat to A/C mode and lower the temperature setting. fan kicks in, the problem isn't in theIf the fan doesn't run, try resetting the furnace circuit breaker. still won't start, call a pro—the fixes shown here won't work. Next, check the outside condensing

The compressor (which sounds like a refrigerator) and fan should be running. If not, follow the troubleshooting and repair procedures shown here. Caution: Turn Off the Power Turn off the A/C and furnace breakers in the main electrical panel before pulling the outdoor disconnect or removing the condensing unit's access panel. use a voltage tester on the wires coming into the contactor to make sure the power The contactor (relay) and start/run capacitor(s) (see illustration below) fail most often and are inexpensive. So it's a safe bet to buy and install those parts right away, especially if your A/C unit is older than five years. The condenser fan motor can also fail, but it runs about $150—hold off buying that unless you're sure that's the culprit. To buy replacement parts, find the nameplate on the condensing unit (not your furnace). Jot down the make, model and serial number (or take a photo).

Get the parts at an appliance store, furnace dealer or online. Anatomy of a Central Air Conditioner Central A/C systems consist of two major components: a condensing unit that sits outside your house, and the evaporator coil (often referred to as an A-coil) that sits in the plenum of your furnace or air handler. in the A-coil picks up the heat from your home and moves it to the outdoor condensing unit. unit fan blows outside air through the condensing coil to remove the heat. The condensing unit houses the three parts replaceable by a DIYer: the contactor, the start/run capacitor(s) and the condenser fan motor. condensing unit also houses the compressor, but only a pro can replace that. The A-coil has no parts that can be serviced by a DIYer. Start with the easy fixes If you're getting little or no cold air, check these three thingsMake sure all the registers in the house are wide open. Then be sure the furnace filter is clean.

Then go outside and clean off the condenser coils (Photo 2). If several registers were closed or the filter was clogged, the reduced airflow could have caused the evaporator coil to ice up and stop cooling yourIf you've changed the filter and opened all the registers and you're still not getting airflow at the registers, deice theMove the thermostat mode switch from “Cooling” to “Off” and move the fan switch from “Auto” to “On.” blower run for at least 30 minutes or until there's good airflowThen turn the A/C back on to test it. If it works for the next 12 hours, you've solved the problem. If the condenser coils are clogged, the compressor can overheatYou'll experience intermittent periods of minimal cooling, followed by no cooling. Even if you're “sure” the condenser coils are clean, clean them again. Flip the A/C and furnace circuit breakers in your main electrical panel to the “Off” position. Next, turn off the power

switch right at the furnace or air handler. Then yank the disconnect block (Photo 1) and clean the condenser coils (Photo 2). If the A/C still doesn't work properly after you've cleaned the condenser coils, installed a new filter and opened all the supply vents, proceed with the following repairs. Many disconnect blocks contain two cartridge fuses. them before you proceed with repairs (Photo 3). A blown fuse is a sign of a failing part inside the condensing unit. replace it and think you've solved the problem. the parts we show here. Then install new fuses and fire up theIf it blows again, call a pro—you've got more serious issues. Inspect the inside of the access panel Follow the electrical conduit from the house—that's where you'll find the access panel. With the power off, remove and store the access-panel retaining screws and remove the panel. Before you replace any parts, check for rodents' nests or evidence

of chewing on wires and electrical connectors. If you find broken wires or chewed insulation and can safely handle electrical repairs, discharge the capacitor first (Photo 4). Then repair the wires and clean out the nest. Otherwise, call a pro. Replace the start/run capacitor(s) All A/C units have at least one capacitor. electricity and releases it during compressor and condenser fan startup to give both motors an extra jolt of power. smooths out voltage fluctuations to protect the compressor and condenser fan motor from damage. Capacitors can degrade slowly, providing less startup powerOr they can fail in an instant. can go unnoticed for a long time, stressing the compressor and condenser fan motor windings, resulting in their early failure. Since capacitors are cheap, it pays to proactively replace yours about every five years. Replacing a capacitor is easy. Just take a photo of the wires before disconnecting anything (you may need a reference

Then discharge the stored energy in the old capacitorUse needle-nose pliers to pluck one wire at a time from the old capacitor and snap it onto the corresponding tab of the new capacitor. The female crimp connectors should snap tightly onto the capacitor tabs. to see if it's tight. If it's not, remove the connector and bend the rounded edges of it so it makes a tighter fit on theWhen you've swapped all the wires, secure the new WARNING: Discharge the capacitor before disconnecting wires or removing it from its bracket. A contactor is a $25 mechanical relay that uses low-voltage power from the thermostat to switch 220-volt high-amperage current to the compressor and condenser fan. A/C contactors can wear out and are at the top of the list of common A/C failures. Even if your contactor is working, it pays to replace it every five years or so. Unscrew the old contactor before removingThen move the wires to the new unit (photo 6).

Reinstall the access panel and disconnect block. circuit breaker and furnace switch. Then set the thermostat to a lower temperature and wait for the A/C to start (see “Be Patient at Startup,” below). The compressor should run and the condenser fan should spin. If the compressor starts but the fan doesn't, the fan motor is most likely shot. Shut off the power and remove the screws around the condenser cover. cover and remove the fan blade and motor (photo 7). the blade and secure the cover. Then repower the unit and see if the fan starts. If it doesn't, you've given it your best shot—it's time to call a pro. Be Patient at Startup A/C units and thermostats have built-in delay features when they're shut down and then repowered. can be as long as 10 minutes. And, if you've subscribed to an energy-saving device from your local power utility, the unit can take even longer to reset. If you've installed the parts shown and reinstalled the disconnect block,