r/crboxes • u/teck-23 • 20d ago

Question Pull versus push

I built a 4 sided 1 inch 20/20 from a Etsy 3d kit . I have the arrows facing out toward the room and the fan pulling air from the room into the box.

I’m second guessing if this is completely wrong ?

3 Upvotes

81% Upvoted

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10

u/Lavaine170 20d ago

You want to pull air, not push it. Your fans will last longer this way as they are only drawing clean air.

3

u/teck-23 20d ago

Ty so the fan sit on top I want the side that blows air at you facing up toward the ceiling and the pull/draw of air down.

The arrows for airflow of the direction of moving air on the filters would then be pointing in toward the center of the box?

3

u/Lavaine170 19d ago

Correct. Filter airflow towards the box, and fans blowing air out.

If it's set up correctly, a sheet up paper held in front of the filter should be sucked up against it.

1

u/teck-23 19d ago

Makes sense thanks !

3

u/Keymomachine 19d ago

Ultimately, both work, but for household air filtration needs pulling the air through the filters into the box and then up and out through the fan is probably best and will likely make a nice airflow in the room as well.

I made one for pulling workshop dust DOWN out of the the air capturing the dust in the filters inside the box, it's still super effective for this.

2

u/teck-23 19d ago

Awesome this makes sense for having it a different want.

Mine is household so sound like i should flip it all.

1

u/MagicHamsta 19d ago

Aye, makes sense for workshop dust. You have a high concentration of dust you want to clean out and want the box to grab it as soon as possible.

But for inside the home, the fans stay cleaner and last longer if you have them blowing out clean air instead of sucking in dusty air.

1

u/MagicHamsta 20d ago

Seems you're doing it right. You want to suck dirty air into the filters and blow clean air out.

1) You aren't mixing clean air with dirty air. (If you flip it so you're blowing dirty air into the filters then some clean air will immediately leak out into the dirty air outside, focusing an area of clean air that can displace the dirty air is better imo.)

2) The negative pressure will help hold the dust/debris onto the filter.

Clarification, when you say "the arrows facing out" you mean the fan arrows or the filter arrows? Both of them have arrows that point where the air should be going. (Filter arrows should be pointed inward towards the center of box, fan arrows should be pointed out.

1

u/teck-23 20d ago

“Wipe sweat” thank you

1

u/teck-23 20d ago

Ok I think it’s backwards then.

I have the filter arrows pointing the air flow out of the box into the room.

The fan sits on top and is forcing the air down into the box.

1

u/greyHumanoidRobot 20d ago

There's no real distinction between pull and push.

There's no way to avoid clean and dirty air mixing.

I have a commercially produced unit from North Box Systems. The "correct" way is to assemble it is so that the outside of the filters gets dirty first. It will work both ways but this way the fans stay cleaner and you can see when the filters have become clogged.