A/C Banging noise on turn on and turn off


  #1  
Old 05-10-18, 10:41 AM
J
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A/C Banging noise on turn on and turn off

Hello everyone,


Curious issue with Central Air,,, When it turns on a loud bang / pop can be heard very close to the furnace / blower unit inside in laundry.

This does not happen with our furnace at all which shares the same air blower etc.

I am wondering what this could be and if I can further troubleshoot this somehow

sound almost like if you hit ducktwork with a rubber mallet.

Thanks
 
  #2  
Old 05-10-18, 02:04 PM
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Yes the ducts are popping. In AC mode the fan runs at a higher speed so you have higher pressure in AC.
 
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Old 05-11-18, 08:55 AM
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You'd have to determine if it was the supply or return duct causing the problem.
Usually it's the return duct and it also signifies undersized return ducting.
 
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Old 05-11-18, 10:02 AM
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thank to both replies!!

is there a way to then minimize or alleviate this? without major rework??

Thanks
 
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Old 05-11-18, 01:49 PM
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It shouldn't take any major rework. You will need to run in AC mode and push around on the duct work till you find the one that pops in.
 
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Old 05-11-18, 02:03 PM
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You can have someone stand there and listen when it pops.
Then you can hit the duct hard..... usually close to the edges to get it to stay in the popped in position.
 
 

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