Heat Problems with 250 HpS

[Cicatriz]

Hi everyone been doing alot of reading but ive still run into some problems. Ive constructed my first grow box that measures 2x4x5. I have my sun system V in there which is 250 HPS bulb + ballast. For my exhaust i have a dayton blower rated at 465 CFM, with passive intake grilles at the bottom of the box. When i run the HPS and fan temps still blow past 100F.

from what i read for proper ventilation you need the fans to replace 3-4x more than the total cubic space in less than 5 minutes. My total cubic feet = 40 cubic feet. So ideally i would want a fan rated at about 120-160. I thought the 465 CFM blower I had would suffice.

can anyone tell me something im not doing right or what im doing wrong?

[justaseed]

where is the thermometer placed? if it's in the dierct light then the reading will be a false high reading. put the thermo at about the level of the canopy and shade it with a peice of cardboard or something. 465 cfm should keep the temp in that size cab the same as the ambient temp of the room the intakes are in. i had a 2x2x2.5 aprox. cab with 150hps and 120cfl with a 180cfm ehaust ant 4inch duct fan for intake and the temps always were the same inside and outside the cab. that means that the air didn't have enough time to heat up before it was exhausted. remember the temp can never go lower than the temp of the air being drawn in (intakes) unless you are using an airconditioner. so if its 90degrees in your house in july then the lowest you grow ttemp could possibly be is 90 degrees(probably a bit hotter) good luck!

[BlueBear]

Yah, what he said. Also, what are the temps in the room? Overall you shouldn't have any real problems with that size fan unless you live in TX and don't have AC.

Justaseed you are my SCROGGING Hero. Have you decided if your going to go hydro on your next gro when you get off...? If so, what system?
Adieu

[Cicatriz]

Justaseed -- three words: SOFA KING GOOD....thats you man...im going to do a dry run of my cab and shield my temp probes and see what real temps im running.

bluebear -- ambient rooms temps are max 83 during the day and 72 at night.

any other comments/input welcome