Why does my inline fan have a 5" intake and a 4" exhaust ?

Just like the title says. I ordered a 4" 190 cfm fan/filter. I quickly notice that the exhaust has a 4" ring, and the intake has a 5" ring. The filter has a 4" ring.

Totally confused here and completely sober

I assume the larger intake is to accomodate the 190 cfm for free air flow.

How do I hook this bad boy up, umm cause 5" intake to a 4" filter does not seem to work for me right now..lol. I got 4" flex hose, not 5".

Also a quick search of my local harware stores and I dont see a 5-4" reducer.

Help a brother out please.

maybe a defect? i don't know, but that is retarded, i would send it back.

http://www.ebay.co.uk/itm/Hydroponic-Grow-Room-Ducting-Cone-Reducer-6-5-4-3-/110623581805?pt=UK_HomeGarden_Garden_PlantsSeedsBulbs_JN&hash=item19c1ade66d

There you go. Theres lots of them on ebay mate

Thanks kingi95012.

After a more extensive search I found an industrial supplier in my area that sells them. I just found it odd it was a different sizes on both ends. I ordered a 6" 440 cfm from a different company hope its same size on both ends!

Cheers !

Yes very retarded, by exactly 1" Found a reducer for $6.00 though.... yippie

your intake is post to be bigger then the exhaust, some say the intake should be two times bigger then the exhaust but i dont totally agree, my exhaust is 4 inch and my intake is 6 inch, at first i had them the same but when i made my intake bigger my temps went down a lil and everything seemed to flow better, hope this helps peace

amrcngror said:

your intake is post to be bigger then the exhaust,

Click to expand...

I would have to disagree with you on that my man ,

You want to exhaust more air out then what is coming in

Why not just keep it the same size all the way threw, keep it smooth no big bends, no need no make it more complicated

No doubt!! Goten is right here. You risk damaging the fan, not to mention stopping or reducing the efficiency of all air flow when you restrict the output. NEVER restrict the outflow. Air movement is an exact science.

I have recently researched air flow for more information. It is correct that you do not want to restrict intake or outflow, and it is recommended that your intake be larger than your exhaust so the fan can spin at its maximum RPM. I have also read here from reputable growers that it is a good idea to have your intake filter larger than the fan. IE: 6" fan, but with an 8" filter. This would allow 'free air flow' at maximum capacity. So I guess my fan is not weird, but just the way it should be.

I guess the rule here would be to match your exhaust hose to your fan size( never smaller ), and if possible provide larger intake to guarantee free air flow.