Banging Fan

For some reason the central heating/cooling fan is making a banging noise. I know it is the fan because when it kicks on, I start hearing a banging noise. It like bangs 4 times a second. 
Does this mean I need a new fan or can it be repaired? Also is this a motor problem or a problem with the fan wheel? It sounds like hitting an air duct with your fingernails.

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Yonatan248 months ago

Our neighbor's AC had a horribly noisy banging sound that didn't allow me to sleep (he didn't even hear it).

If it sounds like metal that's banging on metal, it might be something that has to do with the vibrations, not something that's hitting the propeller, as I thought. If this has been going for quite a while now, it doesn'y make sense that the propeller has survived/has been working properly.

I can't remember exactly what it was, but I do remember that he paid something like $200 to several ⁽ᶫᶦᵃʳˢ⁾ that claimed that they fixed it. We came over and fixed it in under 3 minutes...

ADRIANT28 (author)  Yonatan248 months ago
It sounds more of something with the propellers, when it turns off the banging slows down and then stops when it finishes spinning.

Is this something I can easily buy parts to fix? Or is this something that is complicated where I would probably want to hire a professional or if it is expensive get a new one? I know how to open up the bottom cover of the heater, I did so to look at the fan, and don't see anything, I probably need to open it up.

Is there a repair guide anywhere on the internet?

I think it was the same - don't remember :(

Kiteman8 months ago

Without any other information, my inclination is that the fan has slipped in its housing, and has started to "clip" the side of the ducting.


The ducting around the fan has slipped to make contact with the fan.

In both cases, you probably just need to tighten mounting screws / bolts.

Make sure you cut all power to the fan before opening things up to check screws, and close it up again before re-applying power - the fan may look safe, but a speeding blade can cause a nasty cut or even remove stray body-parts.

ADRIANT28 (author)  Kiteman8 months ago

No, I know it is coming from the fan I turned on the fan without the heater bottom cover to see it and I can hear it coming from the fan.

Kiteman ADRIANT288 months ago

Next step, see if there's anything loose inside the fan...

(Remember, power off!)

ADRIANT28 (author)  Kiteman8 months ago

Ok I will check that. I can't seem to open it up. I removed the screws but cover own't come out.

Hmmm, may need to remove stray body-parts...