HVAC systems include numerous moving parts and separate components, all of which must work together smoothly to achieve the desired results. When one or more of these parts starts to malfunction, owners may receive warnings in the form of odd, annoying, or otherwise abnormal sounds.

Once you know to recognize some of these aural warning signs, you can take the appropriate action to find and fix the problem sooner rather than later, potentially saving your HVAC system from larger problems or even outright failure. The following telltale noises merit your prompt attention and professional evaluation.

Central heating and air conditioning systems rely on a network of ducts to push heated or cooled air into the various parts of your home. Any gaps or malfunctions in the network will allow some of the air to escape, reducing the efficiency of the system and forcing you to run it even harder to achieve comfort.

A breach in an HVAC duct will often create a loud hissing sound as some of the air flows down behind your walls. In such cases, HVAC technicians can track down the source of the leak and tape it up with a special metallic foil.

A more gentle hissing sound may indicate that the problem lies in your air vents, most commonly from a poorly fitted air vent filter. You can solve this problem by replacing the air filter with one of the correct dimensions.

A malfunctioning HVAC system can keep you awake at night or distract you during the day by making alarmingly percussive noises. These noises often point toward a loose part in your blower assembly, as loose parts may knock against each other loudly. Failing motor mounts or bearings may also cause these noises.

More gentle rattling noises in your outdoor air compressor may indicate that leaves, twigs, or other small objects have fallen into the unit or gotten stuck in the fan blades. If your blower makes a sound like playing cards in the spokes of a bicycle wheel every time it comes on, the blower blades may have something lodged in them.

If you hear banging, clanking, or rattling noises, turn the HVAC system off and check your compressor fan for any debris that you can easily remove yourself. More serious issues such as broken components or loose mounts call for professional evaluation and repair.

Clicking noises from your HVAC system don't always indicate a problem. You can expect the system to click whenever it turns on or off because the relay that powers the system commonly makes this sound on activation or deactivation. However, repeated clicking indicates a malfunction developing in the relay switch.

A humming noise can sometimes alert you to electrical issues as well. An overloaded circuit breaker or loose electrical wire may cause this kind of sound. However, your humming noise might also stem from a fan condenser motor problem or vibration from parts rubbing together. Schedule an inspection to pinpoint the exact cause.

Screeching or squealing noises from your HVAC system prove especially irritating. This kind of noise often means that one or more of your system's belts has reached the end of its useful life or that your blower motor's bearings need lubrication. Schedule this service immediately to prevent a blower failure.

A high-pitched whistling or screaming noise could signal danger. It may occur due to abnormally high refrigerant pressure building up in your compressor, possibly due to a valve malfunction. A refrigerant leak can also cause this symptom. 

The refrigerant in HVAC systems poses serious health threats to anyone who inhales it, with consequences ranging from breathing problems to death. If you hear whistling that might stem from a refrigerant leak, turn the system off and don't activate it again until you can get it professionally evaluated.

A steady buzzing noise from your HVAC unit offers less useful information than most other sounds. Many problems can make your system buzz, including many issues noted above. Potential culprits include blower failure, loose fan blades, refrigerant leakage, dirty air filters, and worn-out condenser coils.

You can try to troubleshoot a buzzing noise by checking out the most user-serviceable possibilities yourself. You may spot an obvious cause such as an air filter in need of replacement or debris in the compressor. Otherwise, schedule a professional inspection so that you can find and fix the problem quickly.

When your HVAC system tells you that something has probably gone wrong with it, Central York Corporation can diagnose the problem and make the necessary repairs. Contact us to describe your HVAC symptoms, request an inspection, and schedule any necessary repairs.