OK this is my setup 2 pics included all setup. I have a 30"w x 19.3"d x 69.7"h workforce storage cabinet from home depot as the cabinet. I also have a 400w HPS/MH lamp and ballast, Mylar, a 4" Inline TD-100X 140 cfm duct fan by S&P, a EL-500 Capillary Tube Line Voltage Thermostat to turn fan on when temp reaches what I choose. I also have a Honeywell fan mounted to ceiling of cab. for circulation. Problem is with door closed I get mid 90's and I want the door to be closed. With it open about a foot mid to low 80's. First I had the TD fan exhausting from the top temps where about 10 degrees higher. so I flipped the fan over so instead of blowing air under house from top of cab it blows cold from under house into bottom of cab and rigged a dinky 4" duct fan w/ 80 cfm to exhaust at top of cab. and am now getting the temp readings above. I don't want to blow alot more money unless I know it's gonna work please help! I'm eager to start my new project.
Your exhaust intake looks lower than it needs to be... Also, it would be smarter to use the TD fan for exhaust and the rinky fan, if at all - for intake. You sort of want a negative pressure, and you want the exhaust intake at the very top because all the heat raises to the top.
i do concur with eyecon on this m8 i was told by the shop i got my gear from that you require a exaust fan that is as twice as powerfull as the intake fan to garuntee a negative force in other words push the hot air toward the extracto fan for exhausting outa there
This is exactly what I was worried about if I got a 400w lamp. I have a cabinet about the same size and want to put a light in it like yours but scared of temps. I'm using just a 200w CFL and it took 2 purchases to get the right fan, it seems everyone under estimates how much heat builds up. You do have to move your exhaust right to the top of your box and it would probably help if you put the fan right in the box, you don't want to suck through that much duct work, you lose lots of air every foot you go. its ok to blow though lots of duct but not suck. For a small space like you have you don't want intake fans, they can do more harm then good, just try and seal the box and negative pressure will do its thing as long as you bring your fan in your box or just outside it and get rid of all that duct work in the box. When I relocated my box to a new location the temps decided to jump up to 80 degrees, I had it nice at 75, I thought I would add 2 small intake fans where my air comes in but that actually raised the temps another 2-3 degrees, don't know why but it did. I got my temps down by turning my fan up higher, its louder which I don't want but cooler which is needed. So yeah I'm really interested in seeing you get the temp down to around 75 degrees because we're doing the same thing. First try moving your fan but I think you're going to have to go with 2 exhaust fans. One fan, possibly the one you have now dedicated to cooling the light, of course that means a cool tube reflector. Have it run constantly while the light runs and maybe 20 minutes after the light shuts off. Then have another vortex exhaust fan hooked up on your thermostat to keep the box at the desired temp. Doing that should definitely work, thats what I want to do but I have no money and very little room in my box to work with. Let me know how you make out, we'll figure something out.
Question about your fan, when you look in the fan does it have a normal blade like a fan we use to cool our selfs? When the fan is on could you vacuum with it? If I took my fan and put it on the ground it would suck like a vacuum.
Alright I switched my setup so that my 140 cfm fan is exhausting from the top and since My Cab can't be completely sealed without the doors being sealed (alotta air comes in through the space between the 2 doors) which I don't wanna do cause I wanna be able to check on my babies regularly. So I put the small crappy fan on the intake cause the one-way flow flange was barely coming open on its own. So now I have about mid 90's in there and about 82 with the door open some. I'm guessing I just need a bigger BADDER fan. Oh Yeah the big in-line fan only has about 1-2 ft. ducting when my cab is in place, is that really enough to make a big difference. Quick question, Is it possible for me to put a 250 watt bulb in my 400 watt system to help with temps, or will it just blow the bulb? This is my first experience with HID so I really have no idea.
i recognize that reflector Why not go air cooled hood instead? they are 50-75$ but well worth the money for a cab grow
looking at the size of your cab, it's 4 sq.ft.? I would go with the 250 in that space, just right imo, and probably the s&p would work nicely too? either that or go for a bigger area and get a bigger fan. I don't think s&p are as powerful for the size as other fans, but v. nice fans.
I got my ventilation set up as recommended but light is too hot. So I ask again... Can I put a 250 watt bulb in my 400 watt system? Will the lower rated bulb be able to handle it?
Check your ballast specs but most will not run with just a lamp change, you have to change out the ballast to match the wattage of the bulb you are going to use. If you just decide to put that 250 in there and your ballast is rated for 400, one of two things, will not fire, or reduce the life of the lamp dramatically.