Vac hold down system - BlackBox - filter needed?

[bobmagnuson]

I'm just beginning the process of installing a BlackBox type vac hold down system. Is a filter required on the air stream being pulled through the spoil board into the vac motors?

On one hand, the spoil board acts as a filter of sorts. And on the other, I can see something unexpected begin sucked into an open port, etc.

Thanks,

Bob

[Brady Watson]

A filter is always a good idea. At the very least, a fine metal screen. The filter won't affect airflow that much to cause any noticeable reduction in CFM - unless it gets plugged. A paper automotive type filter or ShopVac pleated filter is fine.

Commercial vac hold down systems typically have a sticker on the filter housing stating, "Check filter once a week". In reality, few do this...and I've seen filter housings completely plugged with debris.

-B