filter and fan cfm question

[UncleMolian]

Hi all,

I have a carbon filter that is rated 360cfm and a fan that is rated at 710 cfm.

how will the difference in cfm affect the function of the fan and filter?

Cheers

 

[Limeygreen]

Is the fan adjustable speed or fixed?

 

[Fly by Night]

Matching fan and filter for best results. Or do a mix n match for a variety of surprises whew

 

[kornwood]

If its not matched as for the cfm or able to hook up a speed controller and slow it down it will suck air through too fast and won't be able to scrub the air

 

[OranguTrump]

If its not matched as for the cfm or able to hook up a speed controller and slow it down it will suck air through too fast and won't be able to scrub the air

Yup - pull air too fast & the filter can't do it's job

 

[UncleMolian]

Hey, thanks for the speedy replies everyone.

it is a 200mm hyperfan with a controller built in. It is currently pulling air through the filter and cooltube with a few bends in the ducting.

The fan seems very restricted with the filter and duct attached. This is all new to me so i am not sure if it seems so restricted from the filter being a lower cfm rating or simply due to normal restriction from the duct and filter. Hopefully that makes sense

 

[spearwarrior]

Cam you do a nose test to the exhaust? Results of said test? I plan on running carbon filters but will be doing real world nose test on a regular schedule to verify they are still working and to determine when active carbon will need to be replaced

 

[MisterBlah]

So, the CFM rating on the fan is the peak CFM of the fan, that is, the CFM it will operate at when under no load. That is, no ducting, no filters, nothing. Put a filter in front of it, the CFM will drop. Put ducting and heat exchangers behind it, CFM will drop. How much? That depends on the fan, the filter, the ducting, the heat exchanger, etc.

The CFM rating of the filter is most likely a peak CFM for effectiveness at odor scrubbing. It will do fine for general particulate air filtration, but odor filtration is a little more delicate.

Your 710cfm fan will most likely operate around 300-500cfm with the filter and ducting in place.

 

[UncleMolian]

So, the CFM rating on the fan is the peak CFM of the fan, that is, the CFM it will operate at when under no load. That is, no ducting, no filters, nothing. Put a filter in front of it, the CFM will drop. Put ducting and heat exchangers behind it, CFM will drop. How much? That depends on the fan, the filter, the ducting, the heat exchanger, etc.

The CFM rating of the filter is most likely a peak CFM for effectiveness at odor scrubbing. It will do fine for general particulate air filtration, but odor filtration is a little more delicate.

Your 710cfm fan will most likely operate around 300-500cfm with the filter and ducting in place.

Thanks mate, so it will be a matter of monitoring the exhausted air for odor and adjusting the fan speed accordingly.

would it be better to get a filter that is rated closer to the max cfm of the fan even if it is pulling through ducting etc and drops the cfm below what is rated at?

 

[Mikell]

The can fan website gives an idea of fan/filter sizing and CFM loss from the filter.

 

[Granger2]

Thanks mate, so it will be a matter of monitoring the exhausted air for odor and adjusting the fan speed accordingly.

would it be better to get a filter that is rated closer to the max cfm of the fan even if it is pulling through ducting etc and drops the cfm below what is rated at?

Yes, it would be better to match the fan/filter. You need the max cfm of the filter to be a bit higher than the max cfm of the fan. I think you would have a hard time down speeding the fan that much. You'd have to slow it to about 50%, and most fans won't take it. Good luck. -granger

 

[hilux phantom]

Yes, it would be better to match the fan/filter. You need the max cfm of the filter to be a bit higher than the max cfm of the fan. I think you would have a hard time down speeding the fan that much. You'd have to slow it to about 50%, and most fans won't take it. Good luck. -granger

this was my understanding as well

 

[hilux phantom]

edit: you can go even higher rating on the air filter and it works better is what I actually heard