Quote Originally Posted by EddyCurrent View Post
I've found it's best to blow air in rather than suck it out. If you suck air out then crap can bypass the filter and find it's way in through gaps, holes, etc. because the air pressure inside the box is lower than outside.
We used to apply the same idea to complete electrical switch rooms.
Ermm I'm no expert on this so I'll bow to your greater experience Eddy but in a dusty enviroment directly sucking dusty air In will surely clog filters faster than pulling air out of a chamber.?