Reducing 6" ducting to 4"

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westpoint

Well-Known Member
I see an edit option but no deleten can a mod help please? double post. Sorry.

Hi everyone. (Running a 3'x3'x72" tent with fc 4800 mars hydro light).
So i got up in my attic and it seems my bathroom poop vent is 4". I have a 6" ac infinity inline fan. I have to go through and inside, up the wall with a 6" round to oval fitting, (to fut between drywall), run in between the wall up 36" to the attic, then either put another oval to round 6" fitting, or maybe they make a 6" oval to 4" round reducer and i can tie right into the 4" poop ducting. The poop vent 4" ducting is approx 10" to the rooffeom the attic floor. Im guessing the longer i can run 6" ducting before i reduce to 4" the better off i am? Itll just require me to rrally have to go deep in attic. (Dont wanna fall through) lol.
What are your thoughts? Should i not be too concerned because my inline fan is a bit overkill for my tent size?
Thanks in advance.

My question is how much performance will i lose
 
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Lenin1917

Lenin1917

Well-Known Member
they do make duct reducers, you could use one pretty easily to do what you’re talking about. But for a 3x3 tent just exhaust directly out of it. As long as you’ve got fresh air coming into the tents room it’s no big deal.
 
Herb & Suds

Herb & Suds

Well-Known Member
bam0813 said:
Oval to round? Don’t think I’ve seen oval ductwork but why not put a 6 to 4 on the fan and go 4 all the way out. Ps hope you mean bathroom exhaust fan and not the stink pipe?
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https://www.lowes.com/pd/American-Metal-Products-Selkirk-Gas-Stainless-Steel-Water-Heater-B-Vent-Gas-Pipe/1000406097?cm_mmc=shp-_-c-_-prd-_-plb-_-ggl-_-PLA_PLB_209_Water-Heaters-_-1000406097-_-online-_-0-_-0&ds_rl=1286981&gbraid=0AAAAAD2B2W8_jj_OjKAsDUTcFamC8IOTk&gbraid=0AAAAAD2B2W8_jj_OjKAsDUTcFamC8IOTk&gclid=EAIaIQobChMInuTp5rmv9QIVailMCh2u2gp-EAQYAyABEgIahPD_BwE&gclsrc=aw.ds
 
xtsho

xtsho

Well-Known Member
When I bought my light it came with a 6" sealed hood. At the time I wasn't paying attention and ordered a 4" fan and filter. I used some reducers I got at Home Depot on each side of the hood and it worked just fine.

I've since replaced everything with 6" but you can reduce from 6" to 4". It's going to be dependent on the size of your grow area. I'm just growing in a 4x4 tent. You wouldn't want to reduce with any significant amount of square footage that requires more flow than a smaller operation.
 
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1212ham

Well-Known Member
Lenin1917 said:
they do make duct reducers, you could use one pretty easily to do what you’re talking about. But for a 3x3 tent just exhaust directly out of it. As long as you’ve got fresh air coming into the tents room it’s no big deal.
Click to expand...
That's what I do, exhaust into the room. When the humidity got too high I vented into the rooms cold air return, works well in the winter.

OP, Keeping more of the duct 6" rather than 4" will improve airflow. I think oval to 6" round, then a reducer to 4" will give best flow.
 
W

westpoint

Well-Known Member
bam0813 said:
I probably should correct myself, this may not be true if your dealing with serious heat issues
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Im wondering if i should run 6" all the way up to the roof vent. The roif vent is 4"", but it will have that entire run at 6" vs mostly 4".
Not sure on heat issues yet. Im waiting fir my light.
 
hotrodharley

hotrodharley

Well-Known Member
xtsho said:
When I bought my light it came with a 6" sealed hood. At the time I wasn't paying attention and ordered a 4" fan and filter. I used some reducers I got at Home Depot on each side of the hood and it worked just fine.

I've since replaced everything with 6" but you can reduce from 6" to 4". It's going to be dependent on the size of your grow area. I'm just growing in a 4x4 tent. You wouldn't want to reduce with any significant amount of square footage that requires more flow than a smaller operation.
Click to expand...
If you reduce from 6" to 4" and then back to 6" it creates a venturi. Venturi effect - pressure lowers going through even the velocity increases. By reducing pressure against the wall. So you don't really lose as much pressure as you would with a straight run.
 
W

westpoint

Well-Known Member
hotrodharley said:
If you reduce from 6" to 4" and then back to 6" it creates a venturi. Venturi effect - pressure lowers going through even the velocity increases. By reducing pressure against the wall. So you don't really lose as much pressure as you would with a straight run.
Click to expand...
Itll just be 6 to 4". Better than nothing.
I plan on running the light with just exhaust going into room and checks temps, then add my ducting out of room and adding ac to see diffetences. Lil experiment.
 
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