HVAC Noise Troubleshooting: Common Sounds and Their Solutions
The HVAC system in your Vancouver, WA home should hum softly and produce minimal sounds during startup. When you start to hear loud bangs and rattling noises, it’s time to call in our team here at Revival Heating & Cooling. If you ignore these signs that something is wrong, you can experience permanent equipment damage, substantial changes in energy efficiency, and even indoor air quality issues. We’re going to dive into common HVAC sounds and their solutions.
The Process of Troubleshooting HVAC Sounds
After first noticing an abnormal noise coming from your HVAC system, it’s important to really listen to what’s going on. It helps if we know the sound occurs during startup, shutdown, during operation, continuously, or occasionally. Also, the location where the sound comes from is important. HVAC sounds can occur inside ductwork, in the indoor handler, or in the outdoor condenser. There may be other factors in play, such as noises occurring after recent changes, like maintenance, repairs, or a filter change.
Rattling Sounds or Vibrations
Rattling sounds or vibrations may come and go as the speed of the fan inside your HVAC system changes. You may also notice these sounds when your compressor cycles on and off. It’s common to experience these noises when there are loose components in your HVAC system. This includes loose interior panels, hardware, or even debris moving around inside your unit. If you’re hearing these sounds from your outdoor unit, there may be sticks, leaves, or garbage that is trapped inside the fan enclosure.
We will power down your system at both the main breaker panel and the thermostat. We will inspect interior components, tighten panels and parts, and clear away any debris that’s present. We will restart the unit and see if the noise has disappeared.
You should inspect your outdoor AC condenser for debris every so often. Keep grass and weeds trimmed back so they cannot cause obstructions. After strong winds or a storm, check the area for any issues.
Loud Banging or Knocking
It’s common for loud banging or knocking to occur because of a shift in air pressure within your HVAC system. Other causes include dampers opening and closing too quickly or thermal expansion and contraction. You may also have alignment issues on your compressor components. You may hear these sounds coming from your ductwork as well as the inside of your main unit.
We will inspect along ductwork joints to see if there are any gaps or cracks that may be impacting airflow. We can use mastic tape or sealants to close open areas. We will also observe the operation of your dampers. Adjusting the speed of damper controls or repairing them can reduce noise. It’s also important for us to ensure your indoor and outdoor compressors are stable. If they are loose because of damaged mounting bolts or rubber isolators, tightening, or replacing these items can stop the noise.
All internal damage and mounting issues should be handled by a professional for safety. Also, professional diagnostics may be necessary if you have warranty coverage you plan to utilize. DIY work has the potential to void coverage in many cases.
Whistling or Hissing
Whistling or hissing sounds usually occur when there is some sort of issue with airflow. This can be the result of ductwork damage that is allowing air to escape during operation. The same is true for your furnace or air conditioner. Leaks should be promptly sealed to reduce noises, but also to protect your HVAC system from strain. We recommend having us seal your ductwork every three to five years to prevent issues such as this.
We will inspect your refrigerant lines in addition to looking for air leaks. If you have a leak in this area of your system, it can produce a hissing sound. Exposure to refrigerant can be a safety risk for both humans and the environment. It’s important to let our knowledgeable team take care of this process for you. We will look for an oily residue around line sets or service valves. This indicates a leak that requires professional repair.
You should inspect your air filter to ensure it is clean. If you haven’t changed it in a while, there could be a problem with airflow. Stick to a schedule of changing this filter every 30 to 90 days.
Squealing and Screeching
As parts rotate within your HVAC system, they should do so relatively quietly. During routine maintenance, we lubricate moving parts to reduce friction which can often prevent odd noises. If this maintenance hasn’t occurred in a while, sounds can start to develop. Common sources of this noise are fan bearings, the blower motor, and belts. These sounds can often point to system strain, which can lead to parts breaking and your equipment wearing out prematurely.
We will inspect and tighten all belts. We may need to replace brittle or glazed belts if they are not promoting proper grip. We will also test capacitor health. Motors can struggle during the startup process if a weak capacitor is present. This can result in squealing or screeching that comes and goes.
Humming and Buzzing Sounds
It’s common to hear a humming or buzzing sound when there is a problem with electrical components inside your HVAC system. These sounds may get worse during startup or after your equipment has been running for a bit. Common areas we inspect are electrical connections, contactors, relays, and refrigerant metering devices. We may need to balance your system or replace the refrigerant valve if this is the source of the noise.
This is one set of noises that we strongly recommend be handled by a professional. Working with electricity can result in electrocution or fire if you aren’t trained and experienced.
Soft Clicks or Ticks
This can be a difficult issue to diagnose because of how light the sound can be. Your thermostat may be clicking or ticking if it’s malfunctioning or taking incorrect readings. We can recalibrate this device to see if that stops the sounds. If your thermostat is nearing the end of its life (which is approximately 10 years), replacement may be necessary.
Short cycling can occur and cause clicks or ticks if there are low levels of refrigerant in your HVAC system or there are restrictions in airflow. Lastly, we will check your control board for relay damage or loose components.
Our team at Revival Heating & Cooling is available to help quickly diagnose HVAC issues and provide prompt repairs. We can also install new heating and cooling equipment and perform routine maintenance. Contact us at Revival Heating & Cooling in Vancouver today to find out more or to schedule an appointment.