The motor, blower and/or steel housing that encloses them is now causing a louder hum or reasonance because I removed the lining material attach to the walls of the steel housing. The material was falling apart and needed to be replaced. What material is available at the home centers that can be used to re-line the enclosure? I was looking at some foam pads (3/4 thick by 4 inch by 14 inch) that are normally used to block air infiltration on both sides of window air conditioners, but I do not know if its the best material to use. What is the ideal material? I just need enough to line an area of about 14 X 14 X14 inches.
Adding thin duct insulation along the walls of the blower enclosure has helped to reduce the reasonance that causes the hum on the steel enclosure. But most of it was coming from the two flanges where the blower mounting plate bolts into. I added both felt and self stick weather stripping in these areas and I manage to lower the reasonance by about 50% and a more acceptable level. However, I did notice that the blower wheel needs to be changed as there is a lot of rust on the vanes and this may also contribute to the noise level. So I will place an order to replace it.