Would it be easier to use the vac when people are awake?

That said, you can use a bathroom exhaust fan, to draw the
heat from the top of the room / closet where the vac
resides. Also, please consider that the sound may be going
out the bottom of the vac through the floor. So, lift the
unit and put sound deadening under the unit.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Robert Green" wrote in message
...
I want to truly silence my Hayden central vac. I bought a
muffler for it,
but it's not really of much use since I've already vented
the exhaust to the
outside via an unused dryer vent. The facts are that it's a
high RPM motor
and it whines and wakes people up when it's in use when
someone's sleeping.
My plan is to box it inside something lined with acoustical
foam and to
provide two auxilliary fans (one low mounted push, one high
mounted pull and
thermal monitoring) to keep the motor cool and shut if off
if the
temperature in the box gets too high. I know the motor's
got a built in
thermal shutoff, but since I am going to be running it in an
abnormal
environment and what a replacement costs, I'd feel safer
with two.

I am going to make some preliminary and crude sound
measurements wrapping in
a different material to see if any has particularly good
sound deadening
properties. Anything I am missing? What sort of materials
(I was thinking
3/4" ply and that bumpy acoustic foam) should I use? How
much distance to
leave around the unit for good airflow? What CFM rate?
What sized fans? I
intend to use 120MM 12V PC case fans, but I'm worried that a
lot of sound
will leak out through the fan ports. I thought perhaps "top
hatting" them
the way chimneys and vent pipes are covered would reduce the
leakage,
especially if the cap had some acoustical foam facing the
fan.

Any thoughts appeciated. Any flames will be cheerfully
ignored!

Bobby G.