Adding a fan always raises my temps

[strain_searcher]

I just added a 90 cfm computer fan blowing over the tops of the plants but that raised the temps like 5 degrees. This has happened every time I do this in any cab. I think it affects the passive intakes in some way. I think I will just get a timer for the ventilation fan so when the inline and light go off this can then turn on and give the plants some air as well as give the inline a rest.

 

[BaboKoyanggi]

Hello,
I'm sure that the fan motor puts out some heat, that might be the reason also, but 5 degrees is a lot more than I would guess a fan motor makes. Unless its a really small grow area.

Peace

 

[Guest]

You know, this might just be a function of where you have your thermometer located. A fan blowing air around inside your cab isn't going to affect the amount of air being sucked in by your exhust/ventilation fan. Perhaps you can try positioning your circ. fan near an intake vent. Doesn't really matter too much if it doesn't blow directly across the plants.......just wanna stir up the air a bit.

Bh

 

[Guest]

Are you fighting natural convection?? It is always best to have intakes near the bottom and exhaust fans at the top. Otherwise, i agree with Bipedalhomined

 

[strain_searcher]

passive are at ther bottom and exhaust the top. I believe the fan blowing accross effects how fast the air is removed from the cab. actaully the whole room got hotter. When i turned off the circ fan ballast and inside temps went down right away. The fan motor on a 90 cfm computer fan is not the reason.

 

[Guest]

Give us a little more info on the cab....size, light, exhaust fan size, passive intake size, ect... I can't see the fan killing the airflow unless its like a vortex inside the cab. How were your plants growing before?? I always see you with the dankness so im guessing not so bad. It could possibly be a short in the motor.....just another guess. I'd say to do without it unless your having temp probs to begin with. you can get a rheostat (sp) that is used to lower voltage. What is the voltage of the fan?? 12v or 120v?

 

[Ncogneato]

Where in the cab is your thermometer located? If it is positioned at the bottom of the cab, that may be the answer. Since heat always rises. When you do not have a fan on your temps will differ from top to bottom, the top being hotter and the bottom being cooler. Now if you turn on a fan, it will stir up the air in the entire cab causing the whole cab to be the same temperature. Which may read higher at the bottom of the cab. I hope that makes sense.

 

[strain_searcher]

Where in the cab is your thermometer located? If it is positioned at the bottom of the cab, that may be the answer. Since heat always rises. When you do not have a fan on your temps will differ from top to bottom, the top being hotter and the bottom being cooler. Now if you turn on a fan, it will stir up the air in the entire cab causing the whole cab to be the same temperature. Which may read higher at the bottom of the cab. I hope that makes sense.

I think thats the answer. Its stirring up air at the top . It still makes everything hotter but nothing too bad. I never use a circ fan and have had the healthiest plants but i just want to experiment a little. If I used a cool tube there would not be any issues but I havent found a good 6 inch one available with reflector.

 

[Guest]

are you using a fan to suck out the heat from the ballast box,that would help alot.

 

[New Holland]

Depending on where the fan is located, it could be turning radiated heat into extra convective heat. If the air the fan is blowing around the cab is passing over the light globe, this air is being heated and then circulated around the cab. Kinda like the same way a hair dryer works. The fan in the hair dryer blowers air through heat elements, in this case your light globe acts as the heating element. I hope this makes sense

 

[Delta9-THC]

I had the same prob .... surprisingly when i removed the fan AND lowered the light the temps dropped... I dont know ...
PEACE