Air Conditioning Trouble Shooting Guide

The air conditioner is often the most expensive item in your home. That may be why most of us have a mini heart attack every time it doesn’t behave as expected. Luckily, most AC failures have a few common causes. Use this air conditioning trouble shooting guide the next time your unit acts up. You may be able to solve the problem yourself.

A Dirty Air Filter

We’ve talked about this so often, we probably sound like a broken record. But seriously, the best thing you can do for your air conditioner is change the air filter regularly.

A dirty air filter compromises the integrity of your entire HVAC system. That’s because a clogged AC filter degrades efficiency and performance dramatically. When that happens, the unit has to work much harder to cool your home. The result is a shorter lifespan and increased utility bills. Your family also suffers poor air quality, which may cause a variety of health issues.

Regular filter changes are good for the air conditionerWhen the AC runs frequently, i.e. during the summer months, you want to change the air filter once a month. During winter months, you can switch to every-other-month if you live in a moderate climate like Phoenix.

Some HVAC companies advise changing your filter quarterly. That advice may be fine in the majority of the country. In the Valley, though, it’s far too dusty and hot to go that long between AC filter changes. And with the average filter costing about five bucks – and the average AC unit more than 600 times that – you can’t afford not to.

Malfunctioning Thermostat

Whenever something goes wrong with an AC unit, we usually recommend checking your thermostat first. A dead battery is the most common cause, so if the settings are correct, try changing the battery.

If your thermostat still doesn’t work, it may be time to replace it, particularly if it’s an older model.

Refrigerant Leak

The refrigerant is how your HVAC system cools the air. If the unit develops a leak, the entire system becomes less efficient and it fails to cool your home effectively.

Our annual maintenance package includes checking refrigerant levels and topping off if necessary. We highly recommend having your unit serviced at least once a year, preferably in the spring or fall. Complete our Service Form to learn more about Northern Air’s maintenance plan.

The Unit Drips Water

Condensation forming in the air conditioner is normal, but a properly functioning unit doesn’t leak water. That’s because the condensate pump removes that condensation (hence the name). If your unit leaks or drips water, you probably have a clog in either the pump or the drain pipe.

Once again, routine maintenance helps prevent this issue.

The Unit Makes Loud or Strange Noises

Banging, popping, squeaking, creaking, and grinding sounds are common indications that there’s a problem with your air conditioner.

  • If the unit squeaks, you probably have a belt issue
  • Grinding sounds indicate a problem with the motor
  • Popping and cracking sounds likely result from a problem in your ductwork

If your air conditioner makes any of these noises, it’s time for a service call.

A woman overheats thanks to a malfunctioning ACThe AC Doesn’t Cool

If you turn on the air conditioner but it doesn’t seem to cool the home, the first thing to check is the thermostat settings. The next thing to inspect is the air filter. If that’s clean or has been changed recently, inspect the exterior unit to see if there’s a blockage of some kind. For proper airflow, you need at least 18″ of clearance on all sides, including above the unit. If the unit is free of obstructions and there’s no issue with your filter, it’s time for a service call.

The Air Conditioner Doesn’t Turn On

The most common reason your AC doesn’t turn on is the thermostat. Make sure it’s set to the correct temperature and is in “cool” mode. When the settings are correct and it still doesn’t start, change the thermostat’s battery. Your unit won’t run at all if the thermostat has a dead battery. If the AC still doesn’t start, check the circuit breaker to make sure you don’t have a blown fuse.

If you do all of these things and the unit still won’t start, you need to schedule a repair.

The Air Conditioner Doesn’t Stop Running

A properly functioning unit stops running once the home reaches the appropriate temperature. When it keeps running, start the thermostat’s settings (you may have noticed a trend here).

If the thermostat settings are correct, you may have an electrical problem. Try shutting down the unit at the breaker. But if the problem continues once you switch it back on, you need to call a service tech.

The Air Conditioner Short Cycles

Short cycling refers to an AC unit that turns on and off constantly. One of the more common causes is dirty condenser coils. If there’s no buildup on the coils, check the unit for obstructions. Debris, leaves, lawn trimmings, trash, and more may pile up around the outside unit and inhibit function.

Other short cycle causes include a dirty air filter and refrigerant leak. If you check all of these and the issue continues, call Northern Air.

Your Utility Bill Shoots Up

One of the most common signs your air conditioner is on the fritz is a sudden, significant increase in your utility bill. Of course, your power bill goes up every summer, so compare it to the same time last year. If there’s a significant difference, your air conditioner is probably working way too hard to cool your home.

As always, first look at your air filter. If it’s dirty, change it and see if that helps.

The problem isn’t always the air conditioner. You may also have an issue with your ductwork. Leaks and blockages in your ducts make it much harder for your HVAC system to cool your home.

Routine maintenance extends the life of your air conditioner and helps discover issues early, when they’re cheaper to fix. To schedule your yearly service, call the pros at Northern Air: 480-352-8710.


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