Confused -- what size DUCTING do I get??

[pftek]

I got a 10" fan and a 8" air cooled tube.

Do i get an 10" duct or an 8" duct?

And the harder question why?

 

[mikeross]

you need to get a reducing coupling from 10" to 8".

remember to wear your safety glasses

 

[pftek]

you need to get a reducing coupling from 10" to 8".

remember to wear your safety glasses

yes but that wasn't the question. i know I need a reducer. I'm asking if I use

10" fan to 10" duct to 10"-8" reducer to 8" light

or

10" fan to 10-8" reducer to 8" duct to 8" light

 

[JamieShoes]

you need a reducer.. but I would always suggest getting the biggest duct where possible.. bigger pipes move more air more quietly


besides when you decide you want more fans or bigger ones, you have duct thats more useful

 

[mikeross]

Oh sorry haha shoulda known better... anyways brother you want your duct work to be 8".

Thats my opinion but that's how i use to run it and it worked out no problem.

 

[gdbud]

10" fan to 36" of 10" duct to 8" reducer to light.
The 36" of duct will allow the air flow straighten out before it hits the fan. This making the fan run more efficient.

 

[benzo]

I have no knowledge of how air flow really works... but I would agree with Jamieshoes, and run 10in ducting then your 10-8in reducer. Because if you ever upgrade to 10in all around, you dont need to get more ducting

 

[mikeross]

Well looks like someone replied as I was posting and suggested you to the opposite then my suggested.

What is the actual layout of the ductwork? How many shades we talking about and how long a run? I honestly cant recall anyone I know reducing the side of their ductwork right at the cooltube.

10" duct > 8" reducer>8"cooltube>10"reducer>10duct

Is that what jamieshoes is suggesting or am i confused... if so that looks odd to me

I run vertical bare bulbs so im the wrong guy to comment haha

 

[JamieShoes]

yeah, creating a bottle neck like that wouldnt be necessarily be "useful"... I hadnt thought about that.. although I still say for later use it makes more sense to get the big stuff early on...

more info on the layout would be helpful


*NOTE - I dont run cool tubes so I never had the bottle neck issue .. my comment is more based on "general" airflow and maybe not best suited for this application...if they were mine though I'd run fat pipes into reducers as this should still mean quieter overall flow/less load on fans

 

[mikeross]

Hold up...

Is this a sealed room with cool tubes or do you have an in and out?

I ask because I assumed this was a sealed room with just cooling for the bulbs. If its a sealed room you want your fan blowing air through the duct. If you have it sucking/pulling, like what everyone who posted in this thread assumes you are, then you will also suck out some odor.

^^^ that is of course if you are running a sealed room and only using the cooling for the lights.

If you have a scrubber on the ductwork and are pulling air rather than pushing I think it may be better to go with the bigger ductwork.


since you are using that big 10" for cooling I assume your running a bunch of lights... are they all in series?

 

[JamieShoes]

I assumed there was a scrubber involved here mike (at the intake end), .. probably guilty of thinking everyone is set up just like mine...lol .. it's easy to forget there's so many ways to run a room

 

[DonkDBZ]

If the lights are in series use 8" between lights then 8"to10" enlarge/reducer to hit main trunk line. Otherwise use a 8-10 at the light. Using a 10 to 8 at the fan will increase the air velocity but at the cost of cfm's and make the fan work harder(most likely increase amperage draw)

 

[calamus]

the biggest ducting you can use is the best ducting, unless it is "not a big deal" thats up to your equipment and you.