Question: My exhaust plenum and stack is really dirty, is there anything that can be done?
Answer: First make sure you position the exhaust filters correctly in the filter banks or racks. Tuck in corners and make sure there are no air gaps that can bypass overspray around the filters.If you still notice excessive overspray in the plenum and stack area, consider stepping up to a more efficient filter to extend the time between exhaust system cleanouts. No filter is 100% efficient so there will always be some residual overspray in the stack.Over the years we did learn a few tricks to make cleaning a spray booth exhaust system a little easier. The two biggest time savers are to grease the fan housing / blade and to apply oil to the inside of the exhaust plenum and stack. The fan blade and housing required substantially less time air chiseling and chipping on subsequent cleanings. The overspray seems to release more easily from inside the stack and plenum area after the oiling procedure.