HELP! exhausting my portable A/C unit properly

Discussion in 'Grow Room Design/Setup' started by PurpleRanger, Aug 10, 2011.

  1. Will an 8 inch exhaust duct, (that is moving all of the air from my closet) being reverted down into the 4 inch UVonair system, restrict my air exhausting power?

    The only reason i am concerned with exhaust being restricted by the UVonair system is: it is pulling air from my 2 small tents and MAINLY my Portable A/C unit.

    I primarily bought the Exhaust fan to ensure the hot exiting air from my portable A/C was removed properly. im afraid the constricting duct on my UVonair will slow down the exhaust strength and cause the A/C units exhaust to back up, which will break the unit? my fans CFM is 440, will that provide enough power to ensure the A/C unit to exhaust properly???? keeping in mind it is pulling air from two tents, each 2x4x6.

    any ideas? i read some where that i can put the UVonair in a large box, after my exhaust fan, to mix w/ the air from my room. so i would have my main exhaust fan feeding 5 feet of duct into a large box w/ Uvonair in it and finally 10 more feet of duct, leading outside? im doubtful that this method will clean the air properly, but i am more concerned with breaking my A/C unit due to an exhaust restriction.


    Have you had to deal w/ this issue? any input would be greatly appreciated.
  2. take pics of your setup and grow supplies...

    visual learner
  3. #3 Dustybowlz, Aug 13, 2011
    Last edited by a moderator: Aug 13, 2011
    I just did this research and yes, it will restrict.

    6" is the smallest you should run and can run with no restrictions up to 10' if you have a built in fan (like 400-500 cfms)

    I honestly just hooked up a single hose portable and am running 14' of the newest grade hvac insulated duct straight ( vitrually no bends) up through attic to roof vent. I didnt add a booster fan (other than built in 500cfm fan) and it works great! Now I got it for like $100 and I know ill have odor issues BUT I needed it because the heat and im under 2 weeks in bloom. Now "I" need to think of odor control! OR switching to a different ac unit.

    Good luck!

    (I just re-read my post and I didnt fully answer your question, my research showed you "shouldnt" go under 5" duct. That is the size of the interior exhaust and reducing it will cause back pressure and shorten life of compressor. NOW, if you didnt run it at full load and "if" you can pull the cfms through 4" duct then technically you could do it. Im not sure If I would do it?)
  4. cool! that info IS helpful! i think im going to exhaust my 2 small tents w/ a 450cfm fan, put a 'Y' adaptor in the duct 3 feet after the fan, and run my AC exhaust hose into the 'Y'. and after that im hoping to run all the exiting air through a larger (wider Diameter) ozone generator in order to not restrict air. i think this should fix my problems. currently im setting up for the same ozone generator but i dont have the 'Y' adaptor, insted i have my tent air mixing w/ my ac exhaust hose in a big box THEN i have my 450cfm moving all of the air out. any placment input would be VERY helpful!

    Option A (current setup): tent air + ac exhaust, mixing in a box >>> Fan >>> ozone generator >>>outside


    Option B: tent air >>> Fan >>> Y duct adaptor w/ ac exhaust attached >>> ozone generator >>> outside

    any input would be rad!
    thanks again about the previous info!
  5. Option b hands down.

    (As a fool) I did my portable set up in like 3-4 different variations. Couldn't get it right. The portables built in fan was allowing all the air to come from the portable (because it was easiest route) and not pulling from hoods/ carbon filter. Air flows like water and will always take the easiest route.

    You "may" (depending on your configuration) want to add a butterfly dampener on the portable ac side of the "Y". That way if it shuts down for some reason it isn't allowing back fed pressures sent down into the portable.

    You "may" also need to make a plenum where this "y" inter section is. You may get a bottle neck effect, due to smaller than required diameter duct. You "may" want to increase the size to 8" after the intercetion of both zones.

    Imo, I would remove odor between the portable ac and the "y". That way you don't bottle kneck the whole system.

    Sorry on my phone.
    Hope this helps.
  6. great info!!! that helps so much! and i learned a new term! plenum! haha!

    ok, so im setting it up! im also using an 8" duct after the 'Y' attachment in hopes to not create any back pressure.
    my only question is about the butterfly dampener. my fan, 'Y' attachment, ozone thing and exiting ducting are all towards the roof of my room. with the butterfly dampener being about 4-5 feet above the AC, will the portable unit have enough power to push the butterfly dampener flaps open. i imagine it would have no problem if the butterfly dampener was installed horizontally, but i think i might have to install mine vertically. will the ac unit be powerful enough to push it open?

    any thoughts would be great!
    and thanks again for the input!!! :)
  7. Your concerns are correct. That's why I was mearly suggesting it and said "depending on your configuration".

    Personally I don't have a dampener on mine as it is its own zone. Imo, I would keep it as free flowing as possible, BUT, if you turn off the ac, it "may" back feed a little.

    Can't hurt but try it with out first?

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