There are plenty of sounds that you probably don't want to hear from your air conditioner, but banging probably tops the list. A loud banging noise you can hear from inside the house isn't just unpleasant; it's almost certainly a sign of a serious problem with your air conditioner. Fortunately, these disturbing noises don't always mean your system is on its last legs.

If you hear these worrying sounds, follow these three steps to protect your air conditioner and resolve the problem before it potentially causes more damage to your system.

1. Shut Your System Down

Loud banging noises are typically signs of compressor issues, refrigerant leaks, and condenser fan problems. Any of these problems can cause further damage to your system if left unaddressed. Once you hear banging from your compressor, start by switching your thermostat's off cooling mode to prevent them from calling for the compressor to turn on.

You can also go outside to your condenser unit and look for the disconnect box. The disconnect should be a gray metal box relatively close to the condenser unit, usually located directly behind it on a wall. Flipping the switch in the box (or removing the fuse for some disconnect boxes) will cut power to your AC and prevent it from turning on.

2. Look for Physical Problems

Since your condenser fan needs plenty of open air around it for proper airflow, branches or other debris can sometimes become lodged in the unit. If an object becomes stuck in the condenser fan, it can create a loud racket as the fan hits it with each rotation. These impacts can also damage the fan by ruining the blades or causing the unit to become unbalanced.

If you notice any obstructions, carefully remove them after disconnecting the system and try turning the unit on again. With any luck, removing the obstruction will solve the problem. If you can still hear noises, there may be damage to your fan, in which case you should disconnect the system again and call for professional help.

3. Make an Emergency Call

When there's no obvious physical obstruction, your next step should be to make an HVAC call for an expert diagnosis. In addition to fan problems, a loud banging or knocking noise can mean that liquid refrigerant is returning to the compressor. This situation, commonly known as slugging, can create high pressure in the compressor cylinder and cause substantial damage to this expensive component.

Never run your system when you can hear this noise from your outdoor unit, as allowing a slugging system to operate can turn a relatively minor refrigerant leak into a wallet-busting compressor replacement. If you're deep in the heat of summer, an emergency HVAC call to get your system running again will be the safest and, ultimately, cheapest option. 

For more info, contact a local company like B & H Heating and Air.