noisy cold air return

[chuckjim]

I have a goodman AEPT 060 5 ton variable speed air handler and heat pump heating and cooling my 4000 sq ft home in washington state. I had a 16" cold air return in central part of home and a seperate 10" return in master bedroom but noticed a lot of noise coming from my 16" cold air return. I decided to add an additional 12" return about 15' away from the existing 16" return in hopes this would quiet the system down. Now the noise is coming from the 12" return(whistling noise). The 12" return is basically a 12"x12" box that transitions to 12" round pipe. From the back of that is 25' of insulated flex duct going into my cold air return box on top of my air handler. Any ideas??

[beenthere]

Your installer didn't size the returns right.
call him back, and have him redo them the proper way.


PS: Don't make duplicate threads about the same problem. I deleted your other thread.

[chuckjim]

ok, i don't think I can blame hvac guys this time. They had originally installed a seperate additional 16" supply and return in a racquetball court in my home but since it seemed to be cold in there and since wasn't being used much I capped off supply and returns to this room myself. Are you saying that with a 16" return a 12" return and a 10" return that I still don't have sufficient return air?

[chuckjim]

I calculated out available sq. in of cold air return to be 391 sq. in.

[beenthere]

Sorry, this is not a DIY site. So we are not allowed to give out DIY advise.

Please read Site Rules Thank you.



But, I wasn't taking about your ducts.

[lentz]

You don't need to blame the HVAC contractor, just ask him to fix it.

[chuckjim]

I took off the new 12x12 cold air return grille and noise went away. I was looking for a bar style grille that has better airflow when I decided to just try and bend the vent slats on existing grille. The noise(whistling) is gone completely and the system is quiet again. Not sure if the 410 cu. inches of return air is enough for 5 ton system or not. I did reduce the fan c.f.m to 1600 cfm down from 2000. Seems to be working great.

[beenthere]

1600 CFM in heating mode. That will tend to shorten compressor life span.
And lower the heat pumps efficiency.

[chuckjim]

Sorry, I lied. It was lowered to 1835 rpms . Does that sound better or is there a reason to leave it on highest setting which is 2050 rpms?

[beenthere]

The 1835 is ok.