# FAQs

## How do I install a flange?

### How much CFM is lost through a 25 ft. section of ducting?

Approximately 3% (straight hard cast) to 7% (fl ex ducting). 1% – 4% additional loss for every 90˚ bend.

### How much CFM loss is there through the 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. Can-Fans® and Max-Fans™ are highly efficient and lose the least amount of CFM when put under a resistance. Can-Fans® will only lose 15%–20% of their air flow through a fi lter. Max-Fans™ only lose 7%–14% of their CFM All other fans lose up to 60% of their CFM. 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 do I size the proper fan and filter to my room?

All Can-Filters® come with a maximum exhaust and maximum recirculation rating, as long as you do not exceed the maximum exhaust rating when matching your fan to your filter you can be confident that the air passing through your filter will exhaust out as clean air. Calculate the cubic feet of the room (Length x Width x Height) and divide that number by the number of minutes you would like to exchange the air in the room (1 – 3 minutes is recommended) that gives you the recommended minimum CFM that you need to exchange the air in that room. (Length x Width x Height) ÷ 3 = Minimum CFM Eg) 10ft x 10ft x 20ft = 2000 Cubic Feet 2000 Cu.ft ÷ 3 = 667CFM A 667 CFM filter is minimum filter size for this size area. Match fan to filter. Consult performance charts to determine which fan will meet the needs of your application.

### Can I push or pull through the filter?

You can both pull through the filter or push air through the filter. If you are going to push air through the filter it is recommended to take off the outer pre-filter and place the pre-filter prior to the air entering the carbon bed.

### What is the Maximum Temperature / Humidity I can run my filter at?

Your Can-Filter® can run at very high temperatures but it is not recommended due to potential overheating to any fans connected to the filter. Try not to run your filter for long periods at or above 70% humidity, the water molecules in the air start to get stuck in the carbon pore structure and slowly diminish the life of the filter.

### Is my fan Speed Controllable?

Yes, all of our fans are speed controllable. Note: Fans running too slowly may overheat, causing the fan to turn off. The 12″ Max-Fan™ requires the use of our variable transformer control. Only use a speed or motor control of the proper amperage to adjust the speed of the fans. Never use a light dimmer.

### What is the warranty on the filters and fans?

Can-Fans® and Max-Fans™ are warranted against defects in material and workmanship for a period of 5 years from the date of purchase.

### Can my filter be refilled?

Technically the filter can be re-filled, but it is not a good idea to self-fi ll the filters. The reason for this is that Can-Filters® has the equipment and facilities to provide a truly packed bed filter. This is not possible at home. The packed bed 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.

### Do I need to replace the pre-filter?

It is a good idea to replace the pre-filter when they become dirty. A dirty pre-filter increases the pressure drop, which will decrease the air flow through the filter. A clean pre-fi filter will also extend the life of your filter and cause it to be more effective.

### How long does the filter last?

The life of a filter is determined by the concentration of the contaminant, the relative humidity and the volume of air being cleaned. Unfortunately, there is no indicator light on the filter that tells you when it is ready to be replaced. Typically 12–18 months is expected of the Original Can-Filter, Although many of them have lasted much longer.

### How do I install a flange?

Take the flange and gasket tape with screws included out of the package, fasten the foam gasket to the underside of the flange by exposing the sticky side of the foam tape and attaching it around the circumference of the bottom of the flange. Once the gasket tape is installed, center the flange on the top of the filter and use the 6 tek screws to fasten the flange to the top of the filter. Be sure not to torque the screws too much as you could strip the steel or warp the flange and create air gaps. You can purchase a flange separate from your filter and fan or have it come with everything in a Box Combo.

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