Good call on the air restriction. My fan makes more noise when I have some of the intakes closed off.
He is using aluminum ducting; when he wrapped it in insulation that dropped a lot of the noise, but it sounds like the fan is humming and it is being resonated by the mounting.
Quote:
Originally Posted by hydro  air restriction could be causing the noise. remove the duct from the hood completely and open the doors so the air is totally unrestricted and see if its still loud, if not re pipe the duct. but you may need some metal duct, the flexible kind will make noise due to the material. the ridges that make it flexible act as a turbulator and the length of the run will dictate sound tone. you want smooth duct like used for heating systems. |