My AC recently (I think, it's pretty new, possible I just didn't notice before) started making a whooshing noise. It sounds kind of like a sudden gust of wind, but it repeats every few seconds. Another way I can think of to describe it: imagine a PC cooler running relatively silent, but still being able to hear it. Now imagine it increasing its RPM noticeably for just around a second. Now imagine it doing this continuously.
It's a Whirlpool split type 12k BTU.
It also doesn't result in air being blown faster but, when you can hear it, if you stand in front of the indoor unit, air stops coming out for like half a second on just one side of the unit. Like the unit "chokes".
Things I've noticed and done:
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efficiency doesn't seem to be affected, it still cools very well, but the sound is annoying.
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it only seems to happen on higher temperatures. For example at 24 and 25 C. Any lower and my unit will start blowing out more air as well, which seems to result in a steady stream of air uninterrupted by whooshings.
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if I lift the front panel, revealing the filters, the phenomenon stops! I thought something might be pushing on the filters, or that it's not closing properly, but I can't see any issues…
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also, if I remove remove the filter on the offending side, it doesn't happen even with the front panel closed.
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it doesn't always happen. Sometimes I run it for hours with no annoying sound, other times it starts a few minutes after turning on the AC. Sometimes it stops for a while.
Any ideas? I tried recording the sound but my phone doesn't really allow you to notice it when it occurs. I can try again if you think a recording would help.
Best Answer
This tells us that it is an Airflow Issue and the culprit is in the filter mechanics.
I am guessing you recently changed filters - perhaps to a new brand or type. Is the filter installed in the correct direction of Airflow - an Arrow on the side should point the way..
I am thinking your filters are the wrong type. The filter is not allowing enough flow (apparently a tight fit) and as the suction (vacuum) builds up the filter moves and eventually it is in a position to allow more air flow and you get the whooshing sound of air passing either around the filter or surprisingly through it.
You can verify the filter brand and type recommendations of your unit - or compare to non offending side - perhaps non-offending side fits loosely and offending side fits more tightly in the filter slots..??