Box fan vs rvk sux wtf.. What now

2cent · Apr 16, 2020

I run 2 600 cooltubes in and out on a rvk 450cmf 6inch a1

And was running another rvk 450 on a filter out.

I wabted more plan was get a rvk l1 890cmf..
But the box 1000cmf was same price...

On powering up box fan it seems not as strong as the rvk?

If i cover the inlet with my hand it almost stoppd
If i cover the 450rvk i almost loose my hand

So what the hells gona happen if i put a filter on it
I am about to buy a filter for 200 quid....
But 6inch 1000cmf filter isnt gonw match the 1000fan if it looses power somuch its less then the 450rvk?

I seriously wish i got the rvk now

Renfro · Apr 16, 2020

If you can provide any link or pic, anything about that fan, the box fan, I could explain better but basically a centrifugal style blower will move air a lot better when there are static pressure losses involved compared to axial fans that are the worst and mixed flow fans fall in between for the most part. I suspect this box fan is an axial fan, when ducted it is dealing with static pressure losses and it falls on it's face.

2cent · Apr 16, 2020

Renfro said:
If you can provide any link or pic, anything about that fan, the box fan, I could explain better but basically a centrifugal style blower will move air a lot better when there are static pressure losses involved compared to axial fans that are the worst and mixed flow fans fall in between for the most part. I suspect this box fan is an axial fan, when ducted it is dealing with static pressure losses and it falls on it's face.

Its a torin sifan 1000. Ive put a brand new capacitor on it old one was giving voltage drops on meter. Now its running 100% to spec.
Just doesnt seem to pull like an rvk does. I cover thrm and thell suck to hell. This box fsalmost comes to a stop

Renfro · Apr 16, 2020

Those old squirrel cage fan designs are commonly used in central air systems over here in the US. They typically move a lot of air pretty efficiently. They aren't asked to fight the restriction of a heavy filter though, in fact HVAC techs are commonly called out because someone installed a more restrictive HEPA filter and it killed the CFM enough that the evaporator coil freezes up when the AC is running.

I suspect that you will have a lot better luck with the RVK 890 CFM.

coreywebster · Apr 16, 2020

Usually a box fan has a bigger drop off with resistance but after that its consistent, where an rvk will continue to drop off the more resistance is added.

What's the spigot size of the box fan? Bigger than the 6" RVK

I use box fans these days with far less cfm and they pull through my filters without issue.

Renfro is right though, you will maybe lose 25% of an RVK @890cfm where you could lose up to 50% with the box fan, meaning the rvk would win in overall cfm , but that assuming only a few meters of duct, a bend and filter, if you have 10+m, filter and several bends the Box fan may come out on top

2cent · Apr 16, 2020

coreywebster said:
Usually a box fan has a bigger drop off with resistance but after that its consistent, where an rvk will continue to drop off the more resistance is added.

What's the spigot size of the box fan? Bigger than the 6" RVK

I use box fans these days with far less cfm and they pull through my filters without issue.

Renfro is right though, you will maybe lose 25% of an RVK @890cfm where you could lose up to 50% with the box fan, meaning the rvk would win in overall cfm , but that assuming only a few meters of duct, a bend and filter, if you have 10+m, filter and several bends the Box fan may come out on top

Why do they sell em with filter kits then bosting them so good?

Il get an rvk...

I could use it for intake i guess. Quieter than an rvk

Think the l1 rvk 6 800cmf wil blast the 1000 box to bits so neg pressure stil be there? I mean i can stockin the inlet and it wil restrict up lol or use controller

coreywebster · Apr 16, 2020

2cent said:
Why do they sell em with filter kits then bosting them so good?

Il get an rvk...

I could use it for intake i guess. Quieter than an rvk

Think the l1 rvk 6 800cmf wil blast the 1000 box to bits so neg pressure stil be there? I mean i can stockin the inlet and it wil restrict up lol or use controller

Because they are quieter and they are good , depends on the situation your using them in.

Like I say all my fans are box fans because I like low noise and they all do the job with filters.

That said they sell a lot of shit that isn't good for the job they are selling it for, but I don't count box fans in that category.

Reason I asked about spigot size is because if you have an 8" box fan and a 6" RVK and put your hand over the intake the 6" is going to feel like more pull. Doesn't mean it is.

2cent · Apr 16, 2020

coreywebster said:
Because they are quieter and they are good , depends on the situation your using them in.

Like I say all my fans are box fans because I like low noise and they all do the job with filters.

That said they sell a lot of shit that isn't good for the job they are selling it for, but I don't count box fans in that category.

Reason I asked about spigot size is because if you have an 8" box fan and a 6" RVK and put your hand over the intake the 6" is going to feel like more pull. Doesn't mean it is.

Understood. But the air its pishing out sat next to an rvk isnt half as powerful.

The box fan when i introduce my and neqr it the fan literatly slows down to nothibg so isjt gona filter anything?

Im like right now about to buy another fan again lol
So option is downgrade on filter brand to a good 1 stil
Rvk 6inch 800cmf 600x150 filter
Or
Use the box 1000 and buy a 1000cmf mountain air
Filter 1000x150..

I jusy dont feel the box will extract when i put the filter on... I feelvlike the. Smaller rated rvk will outpreform it. Meaning the mountain air wont be gettin the 1000cmf it needs to work?

If i had to rate it by feel looking at a 6inch rvk 450cmf...id rate the box fan at 350 and drop to 150 with hand not even covering it

coreywebster · Apr 16, 2020

2cent said:
Understood. But the air its pishing out sat next to an rvk isnt half as powerful.

The box fan when i introduce my and neqr it the fan literatly slows down to nothibg so isjt gona filter anything?

Im like right now about to buy another fan again lol
So option is downgrade on filter brand to a good 1 stil
Rvk 6inch 800cmf 600x150 filter
Or
Use the box 1000 and buy a 1000cmf mountain air
Filter 1000x150..

I jusy dont feel the box will extract when i put the filter on... I feelvlike the. Smaller rated rvk will outpreform it. Meaning the mountain air wont be gettin the 1000cmf it needs to work?

If i had to rate it by feel looking at a 6inch rvk 450cmf...id rate the box fan at 350 and drop to 150 with hand not even covering it

Filters don't need amount of cfm to work, they last longer with less cfm, you just don't want to use more cfm than they are rated for.
All my tents have 8" filters and run at 1/10th of the max rating, means my filters lasts years longer than rated.
Within reason the slower the air, the more contact time the air has with the carbon and the more likely it cleans 100% of the smell.

If your in doubt then go with what you know. An RVK is a pure work horse and will do what you want without question. They are just a bit loud for me these days.

2cent · Apr 16, 2020

U saying the box fan will still be doing its job?

Main reason i got it was i wanted to get double the power my 450rvk has.... Needed more cooling.

Means id put the 450 intake and box on filter out..

Just worried it wont preform just if i get the rvk now... Im wasting another 150 quid spent on the box fan lol.

Tell me what to do haha heres a pic
Where it says 200 i meant 150typo

coreywebster · Apr 16, 2020

2cent said:
U saying the box fan will still be doing its job?

Main reason i got it was i wanted to get double the power my 450rvk has.... Needed more cooling.

Means id put the 450 intake and box on filter out..

Just worried it wont preform just if i get the rvk now... Im wasting another 150 quid spent on the box fan lol.

Tell me what to do haha heres a pic
Where it says 200 i meant 150typo

Try it and see before you spend more money, or send it back get a refund.

Cant tell you the exact performance drop on the box fan.

Box fan vs rvk sux wtf.. What now

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