How To Size Fan to Filter
To match a Can Filter for your size growing environment, use this formula: Length x Width x Height divided by 3. This figure will give you the minimum recommended CFM for your fan. Then match your inline fan to the size filter you need by getting one that’s within the range that the Can Filter can operate within.
Example, 10 x 10 x 20 = 2000 Cu. Ft.
2000 Cu. Ft./3 = 667 CFM
667 CFM fan is the minimum fan size for this area. After establishing fan size, match it to appropriate sized filter, IE, Can 100.
How Much CFM Loss Through A Carbon Filter?
Every different size of filter provides a different resistance to each different size and style of fan you put on it, a filter at the maximum exhaust CFM rating has approximately 0.7 wg. pressure drop. All Fans will have a lower CFM at a higher pressure. For Example at .5 wg the 10″ Max-Fan goes from 1019 CFM to 885 CFM, the 12″ Max-Fan would go from 1708 CFM to 1595 CFM.
How much CFM is lost through a 25ft. Section of ducting?
Approximately 3%(straight hard cast) to 7%(flex ducting). 1% to 4% Additional loss for every 90° bend.
Do I need to replace the pre-filter?
It is a good idea to replace the pre-filter when they become dirty because the pre filter is blocking larger dirt and dust particles from getting into the pore structure of the carbon, a dirty pre filter increases the pressure, which will decrease the flow through the filter.
Can my Filter be refilled?
Technically the filter can be re-filled, but it is not a good idea to self-fill the filters at all, the reason for this is that Can-Filters uses an industrial shaker with timed intervals and a dust extraction system, to ensure a packed carbon bed. This eliminates the possibility of preferred air channels through the filter, because as we all know, air does not wait in line to go through a filter it finds the path of least resistance and crowds in. So if you tried packing the filter yourself, as soon as you got it as full as you think you could get it, attached a fan and turned it on, the fan would vibrate the carbon, and over time the carbon would settle and you would be left with air gaps all over the place presenting the air with channels to flow through the filter and possibly leave untreated.