8"air cooled hoods

[jase_ventura]

here's my query guys. I've got 6x 1000w hps in sealed ac hoods and just wondering this. How many can I link up, I have 2 rows of 3 lights with 8" flanges, I am yet to buy any fans for these as I'm trying to save on one fan by buying a bigger fan. Would it be possible to cool a full row of 3 lights on one large fan. The air will be ducted from the lights to my passage outside to help heat my house. And again I very much doubt this but ill ask any way, would it be possible to just use one huge fan and use a splitter to duct the air through both rows; cooling 6 in total. This might sound stupid to you experienced guys but ill never learn if I don't ask eh? Thankyou for takin the time to read this, peace out!

 

[Chillville]

Doesn't sound stupid at all. You don't mention how long your ducting is but it doesnt sound like you are running it very far. I personally would go with (2) 10 max-fans running three rows of lights and put them on a fan speed controller....set to about 80%. Using one fan may be a hassle trying to duct it all together, you will get better flow from the (2) 10" IME. I do think that you can use (2) 8" max fans instead and be just fine but I would run them at 100%. I always go with a bigger fan than I need and reduce the speed. When fans run at 80% power they seem 50% quieter.

 

[hiboy]

bro i have 7 lights linked up on an 8 inch wind tunnel fan
no problemo.... you can even Y your lights together if u dont wana put them in a row.
Remember if u suck the air at the end ull suck the air from the grow room and the smell.
But if you push the air before the lights you wont get any smell
h

 

[jase_ventura]

bro i have 7 lights linked up on an 8 inch wind tunnel fan
no problemo.... you can even Y your lights together if u dont wana put them in a row.
Remember if u suck the air at the end ull suck the air from the grow room and the smell.
But if you push the air before the lights you wont get any smell
h

Yeah how is this though if I'm using sealed hoods? Someone else has said that if imy fans suck through the lights it will smell but I just can't get my head round it cos I mean the got gaskets n stuff. In my head this means that using co2 would be pointless cos if smell gets sucked into the HOOD > FAN > OUTSIDE, then surely the co2 will. Are wind tunnel fans much good? I was gonna go for a can fan 8" for each run and run them both at 80 and use some inline boosters between the hoods as I can get them really cheap. In total on both runs there will be approx 8 ft of ducting this includes before the hoods, between the hoods and after the hoods, about 4ft per run of straight tight ductin should be sweet right?

 

[Danoid]

Fans in my experience always work better pulling the air through the light. At the hardware store they sell silver foil HVAC tape that you can use to tape the lense in the reflector. I have had many "factory sealed reflectors" and they never sealed. so I would tape the safety glass in with like a 1/4'' on the glass. You will not loss many reflected lumens and the safety(smell) and the saving if you are CO2 will far out weigh the reflected lumen loss.That foil tape will cut you quick so take an old creditcard and use it to rub the tape down to give it a good seal. Also stay clear of the reinforced foil tape as it is a bitch to remove where the foil tape peels right off. As far as booster fans in between the lights I have tried that and it was counter productive when I was using a can fan or wind tunnel. The can fan spins at a much higher RPM than the booster so the booster would restrict more air than it could move. I can't remember where I read it but they say you want 200 cfm of air per light in sizing you fan to the set up. Hope this helps and good luck in your endevor.

 

[hiboy]

They always leak a little thru the gaps,,,,,
and if you tape like mentioned above its a pain in the ass to change lamp if you veg in there too for a bit,, or if you want to clean the glass. that tape almost gets bonded to the metal due to the high temps

h

 

[Danoid]

Hiboy I agree 100% with you on the lockdown of the tape it can be a bitch to remove. What I do is just remove the duct from one end and go at it that way for bulb replacement or lense cleaning. Good Luck

 

[naga]

the problem i had doing a split set up was leaks everywhere.i taped up the hoods with scott33 tape and used a two coat of duct seal paint on the splits.

just walk around your sealed hoodeds with burning incense sticks to find the leaks,there everywhere.

 

[jase_ventura]

They always leak a little thru the gaps,,,,,
and if you tape like mentioned above its a pain in the ass to change lamp if you veg in there too for a bit,, or if you want to clean the glass. that tape almost gets bonded to the metal due to the high temps

h

Yeah dude I get it now, so I want positive pressure inside my hoods so at the worst my lights would blow a small ammount of heat from the seals as apposed to having a negative pressure and have a small but strong wiff of the good stuff blown into my house, good advice mate thanks. Maybe some sort of solvent would get the tape off easier something like upvc cleaner like chemi clean or something, works great for silicone on tiles and that shits a bastard to get off.

 

[jase_ventura]

Fans in my experience always work better pulling the air through the light. At the hardware store they sell silver foil HVAC tape that you can use to tape the lense in the reflector. I have had many "factory sealed reflectors" and they never sealed. so I would tape the safety glass in with like a 1/4'' on the glass. You will not loss many reflected lumens and the safety(smell) and the saving if you are CO2 will far out weigh the reflected lumen loss.That foil tape will cut you quick so take an old creditcard and use it to rub the tape down to give it a good seal. Also stay clear of the reinforced foil tape as it is a bitch to remove where the foil tape peels right off. As far as booster fans in between the lights I have tried that and it was counter productive when I was using a can fan or wind tunnel. The can fan spins at a much higher RPM than the booster so the booster would restrict more air than it could move. I can't remember where I read it but they say you want 200 cfm of air per light in sizing you fan to the set up. Hope this helps and good luck in your endevor.

Thanks for this advice about the booster fans, I think I'm still gonna buy them just incase I could ever use them for another project cos I mean ten pounds is like a quater of what they cost in shops. So by that calculation a 735 cfm fan for each light run would be a good idea. I'm kinda warming to the idea of turning my hoods sideways and buyin 3 smaller fans, basically just to get more even light coverage over the whole canopy, at first I thought I could just use the two and have them sideways but then my ducting would be turning corners like crazy and probably conduct more heat than I'm venting, what's ur thoughts on this ?

 

[Danoid]

You have to remember every 90 degree elbow cost you around 60 cfm or every 10' of ridged duct cost you around 60 cfm. Flex duct is even more especially pushing air thru it. I struggled for years trying to push air thru my lights and it never worked out for me. On one occasion it did work out was when using cool tubes and ridged duct with no turns. That was the only time it did not make a difference when I switch from pushing to pulling air. Using ridged duct left no room for adjusting individual lights according to canopy growth. Over time in that particular room I switched out the ridged for flex and there was no way I could push the amount of air needed thru the flex duct so I had to switch ends with the fan and pull it thru. I personally think it is the turbulance that is created in the reflector and the flex duct from pushing the air into it that fight the air flow going out. Also always buy a bigger fan than you need because you can use a fan speed controller to slow it down to your specifications. You can buy a router(wood working) speed controller from harbor freight at half the price of a fan speed controller from the hydro store. I know there is alot more info on the web so you could try and use your google fu and look around for a "ductalator calculator". Hope this helps and Good Luck

 

[Danoid]

I forgot to add when using the non insulated flex duct check weekly for air leaks at the hottest part of your setup as the hot air does a number on it and it will crack and get pin holes in it. My set up now on my veg side gets changed every month because I have 2 1000watts going thru it. Flower side gets changed every 3 months (security) but it is a whole different set up and I have each individual light going to a header style set up. Good Luck