“Whap, Gurgle, Bang, Rattle, and Squeak” – Why is My HVAC System Making Sounds?
We have all been there: trying to describe to an expert the exact sound a piece of equipment is making. We may even create new words to get it just right, such as “Flizzle, Jonk, and Bloof.”
There is a problematic reason for most noises coming from your HVAC system, particularly if they are loud and frequent enough to be noticed.
Important note: Attributing likely problems to the unusual sounds of an HVAC unit is certainly not an exact science, rather it is a “best guess” situation – professional HVAC service technicians are, by far, your best bet for deducing your system’s issues. The most important thing to remember is that in many situations, it is recommended that your HVAC system be turned off until the problem can be identified.
“Groaning” and “Growling”
A loud groaning or growling sound when starting the A/C on a system often leads a professional to the compressor. If your compressor has a “hard starter,” the groaning is often an excess of amperage to get the unit started. An HVAC service technician can determine if a “hard start kit” will fix the problem, but if not, the amperage needed to start the compressor would be measured, and if the unit requires a high amount of amperage to start, it is time to get a new compressor.
“Screeching” and “Squealing”
As unpleasant as these sounds can be, there is a good possibility that they may indicate a simpler solution. Like most engines, and HVAC unit sometimes needs some upkeep by way of proper lubrication or the replacement of a loose or damaged belt. A belt replacement is usually inexpensive (although not recommended to do yourself). An HVAC service tech can also determine which squeaky wheel needs the oil. Important: WD-40 and 3 in 1 oil are not recommended – an HVAC motor required a heavier lubrication.
“Water sounds” in the HVAC system (usually most detectable when the unit is first shut down), likely indicate a problem in the refrigerant lines. The gurgling sound is air trapped in the liquid coolant lines and it should be removed. A technician can then determine if the system has a leak somewhere, as the infiltration of air would simply not happen if the lines are properly sealed.
Loud “Thunks” and “Clunks”
These deeper sounds may indicate something serious. Sounds like this can sometimes be attributed to an imbalance in the fan or mounts that have become loose. The first thing to do is shut the system off right away to avoid any further damage until the problem can be located. If the fan on the unit has a damaged or missing blade, it would likely result in these off-balance noises. Just as serious, it may also be a loosening of the fan’s mounts or the compressor motor mount itself. In either case, the unit is dangerously close to causing more damage when the unit or fan becomes disengaged and does widespread damage.
“Rattling” and “Clicking”
As with any other machine, over time an HVAC system can develop small sounds such as light rattling or clicking, but it is also not something that should be ignored. The louder the sound is, the more imperative it be addressed. Rattling can indicate that something is loose, from sheet metal screws to a loose blower fan. A small amount of clicking is normal upon startup, but continued clicking might be the result of a bad relay switch or the fan touching something it shouldn’t as it turns – if that happens to be wiring, there can be exponential consequences; therefore, an HVAC service technician is always recommended.
Contact Entek HVAC of Longview, Washington to cure your noisy system
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