Venting/ Exhaust Question

[GMO]

i found this which may be useful https://www.engineeringtoolbox.com/equi ... d_443.html

[GrowGlow]

with constant high temps i would personally worry about pushing an 8" through a 6" hole. its just adding load to the fan which makes it work harder getting hotter and reducing its life. if you were running at say a max of 75% on the fan speed controller that might help reduce the laod but then are you better off going for a 6" that you can run at 100%?

altho saying that, i run a 6" outtake throw a 4" hole in chimney breast and just allow the excess to recirculate

75% of 8 inch 760cfm is 570cfm, which is still significantly higher than the 460cfm of a 6 inch run at 100%.

Also, I wouldn't say high ambient temps are constant. Night time temps drop and it drops further when it rains. So for both temps and RH, there will be both highs and lows throughout the day.

Thinking about taking measurements and getting a custom made adapter for 8 inch hole. Seems easy enough. A rectangular board of about 2metres x 0.45metres or so with a 0.20metre (8 inch) diameter hole on top. Any ideas what material would be easy to accomplish this? Aluminum? Plywood?

[GMO]

We have a member who uses plant pots as reducers. Cheap option

MDF is always easy to work with

translated from the bongo of the canna jungle

[GrowGlow]

We have a member who uses plant pots as reducers. Cheap option

MDF is always easy to work with

translated from the bongo of the canna jungle

Whats MDF?

[kbag]

Personally for the price of 2 pvc reducers i would go with that and do a few test runs first. Your fan is more than adequate for the tent size @ 1241 cm/hr if you can keep the ducting as straight as possible the only reducer that may affect the output is the 8" - 6".
I personally think the reducer will make very minimal difference.

[GrowGlow]

Personally for the price of 2 pvc reducers i would go with that and do a few test runs first. Your fan is more than adequate for the tent size @ 1241 cm/hr if you can keep the ducting as straight as possible the only reducer that may affect the output is the 8" - 6".
I personally think the reducer will make very minimal difference.

Makes perfect sense when you put it that way!

Thank you so much for the advice. Thats really what Im looking for. I'm not expecting anyone with my exact conditions to chime in and give me the perfect solution. Thats too much to ask for imo.

The next best thing would be for experienced users to chime in with their best educated guesses if I may?

Unless in a sealed room, most growers would experience high temps and RH at some point during the year. So the conditions are not that different. Only difference is, I've never experienced growing in tents before so can't get the feel for it.

So i guess what I really need if to help me get a feel for it? Perhaps to vet out any major mistakes?

So far, I feel the setup is pretty sound. A 4×8 tent using a 760cfm, 8 inch exhaust fan with variable speed and environment control. The exhaust fan will be fitted via a reducer to a 850cfm 10×24 carbon filter. The 8 inch duct will travel no more than 3-4ft before reaching the 6 inch vent hole. Possibly even shorter. Due to the exhaust fan probably never needing to reach max power or even close, I feel the reduced 6 inch vent hole should not matter too much?

When using such a large exhaust fan, will my tent suck in and collapse if I accidentally turn it to max? Like if I set environment control to 25C and 60H but ambient temps are always higher than that, so the fan keeps running at max. Will this destroy the tent or something? Might be a really dumb question but thought i should ask.

[kbag]

When using such a large exhaust fan, will my tent suck in and collapse if I accidentally turn it to max?

If its a quality tent then certainly not. That being said i have seen broken poles at the weld points when powerful extraction as been used. Make sure your passive vents are open before turning the fan on and zipping up the tent tight. The tent should suck in as this is what you want (negative pressure) to stop smell leaks. As you are using a fan controller you can dial in to suit your needs.
I do not know what size room your tent is in, but the room where my tent is situated 9ft x9ft and with a 8" fan it creates enough negative pressure to pull the door open if not latched.

[GrowGlow]

When using such a large exhaust fan, will my tent suck in and collapse if I accidentally turn it to max?

If its a quality tent then certainly not. That being said i have seen broken poles at the weld points when powerful extraction as been used. Make sure your passive vents are open before turning the fan on and zipping up the tent tight. The tent should suck in as this is what you want (negative pressure) to stop smell leaks. As you are using a fan controller you can dial in to suit your needs.
I do not know what size room your tent is in, but the room where my tent is situated 9ft x9ft and with a 8" fan it creates enough negative pressure to pull the door open if not latched.

Great info!

My room will be slightly bigger at around 13×11×10 or so. It will easily fit the 4×8 and perhaps another 5×5 in the future.

[Zombie Nation]

I'd be wary with online deliveries these days...some couriers ram stuff into their vans to maximise on 'paid per parcel', if you're not in they will leave anywhere as they dont get paid to bring it back and item wrapping is often damaged loosing the any form of stealth option...especially if left with neighbours with ripped wrap...now they know ;)

I goto a hydro shop but not a local one & pay with cash...less likely to be spotted by anyone I know and no paper trail :)

[Zombie Nation]

We have a member who uses plant pots as reducers. Cheap option

MDF is always easy to work with

translated from the bongo of the canna jungle

Whats MDF?

Bits and pieces of scrap wood, sawdust, the odd TCT saw tooth chip, sweepings up, maybe a cigarette butt or two....lots of sticky resinous glue and a big 200 tonne press...all minced up and stuck together :)

If you do get some...don't breathe in the dust when cutting, its carcinogenic...