In take air to cold for light cooling?

mountainboy

mountainboy

Well-Known Member
Hi all, Was wondering if air can be to cold to run thru my lights hood? I grow in my garage and draw air str8 from the outside,which at this time of year can be in the teens to below zero soon. I have 8in. intake and exhaust on hood with a 400cfm fan on the exhaust end. light stays cool and dont see any diminished light out put but wondering as it gets colder could this cause a problem? has anyone ever been in the same situation and did you have any problems?
Thanks in advance for any responses.

Side question, could I run into issues with ballast? I also run that outside the grow room. It is in the garage which I dont heat. Ballast is magnetic type & air cooled with built in muffin fan.
 
un named

un named

Active Member
get a fan speed controller and monitor it for a day or two. i would say moister could be a problem
 
beuffer420

beuffer420

Well-Known Member
I had a buddy do this with three thousand watts. In the winter he came into his grow to find his hoods (8inch big foots) holding water and dripping all over. Once the air passing by your lights gets too cold moisture begins to form. I guess just watch it and make sure you don't see any condensation forming
 
mountainboy

mountainboy

Well-Known Member
Thanks guys. The duct work runs 7ft before it hits the light. I have noticed condensation on the first foot or soon of duct work and right where it connects to out side I even had a thin layer of frost. I will keep an eye on condensation. No issues YET with anything at the hood or the exhaust side. I am going to measure temp thru out the duct system, my main concern was blasting a 1000watt bulb with really cold air and having it explode. I know water will cause that.
I would just draw air from inside the room and disconnect the intake side, but then I'll have to redesign my whole intake and exhaust air system,along with temp controls. But if thats what it takes.
 
legallyflying

legallyflying

Well-Known Member
If your grow room humidity is above around 50 or so, where it should be, your going to have condensate problems. You can fix some of this by installing a T right when the duct enters the garage. Then use a flapper or tape or whatever to partially close the T. That way you get a little Warner air from inside the garage to mix with the outside air. It will help attenuate the condensation. You can also create a big dip in your duct to help make the condensate drip off your line before getting to the tent

Whatever you do, don't insulate the duct...the condensation will just move farther down the line.

Lastly, you should probably be running a heater to avoid light on/off temp differences of greater than 10 degrees. This will cause slower growth in addition to the dreaded stretch.

Cheers
 
mountainboy

mountainboy

Well-Known Member
legallyflying said:
If your grow room humidity is above around 50 or so, where it should be, your going to have condensate problems. You can fix some of this by installing a T right when the duct enters the garage. Then use a flapper or tape or whatever to partially close the T. That way you get a little Warner air from inside the garage to mix with the outside air. It will help attenuate the condensation. You can also create a big dip in your duct to help make the condensate drip off your line before getting to the tent

Whatever you do, don't insulate the duct...the condensation will just move farther down the line.

Lastly, you should probably be running a heater to avoid light on/off temp differences of greater than 10 degrees. This will cause slower growth in addition to the dreaded stretch.

Cheers
Click to expand...
Thanks for the feed back,but I should have explained my set up better. I'm not growing in a tent. I built a 9x9 room inside my garage. It is fully insulated and has great climate control in that space. The garage it self isnt heated but the room is.
 
N

NoBarriers

Well-Known Member
I run cold air through my hoods without any problems. I draw air from an unheated space through 2 1000 watt hoods and out into another space. Cold air doesn't hold as much water, I have never had an issues with moisture. I run a 6" fan on full. There is no problem with ballasts and cold air, street lights, outside lights etc all run in the cold.
 
bowlfullofbliss

bowlfullofbliss

Well-Known Member
I also push fresh outside air through my lights. I run 3 1000's with a 6" inline, and have never had an issue with moisture in the hoods, at least not yet. Its been a few years in this particular space too.
 
legallyflying

legallyflying

Well-Known Member
NoBarriers said:
I run cold air through my hoods without any problems. I draw air from an unheated space through 2 1000 watt hoods and out into another space. Cold air doesn't hold as much water, I have never had an issues with moisture. I run a 6" fan on full. There is no problem with ballasts and cold air, street lights, outside lights etc all run in the cold.
Click to expand...

Ohhh, street lights run in the cold. OK then, yeah, pump all that cold air through your ducts. Your right that cold air doesn't hold as much moisture... but..its not the cold air in the ducts that causes the problems... its the warm air in the grow room..and the moisture it contains.. that condenses on the cold surface of the ducts.

Air from an unheated space inside your house is fine..its not that cold. Cold air, directly from outside is going to cause condensation unless the air in your room is exceedingly dry.

Its not going to hurt your bulb or balllast or anything, its just going to make a mess.

I thought I would insulate my ducts to get them to stop dripping. Then there were pools of water on the glass of my reflector. ANyways, I guess jsut see what happpens.
 
N

NoBarriers

Well-Known Member
I know how condensation works, I just never had an issue with it pulling unheated air through my hoods in two winters. The air is as cold as outside and i live in new england so sometimes its really cold. Sucks that you did and can see how it can happen. Maybe its the volume of air going through the hoods that cools it down too much. I used a 6" fan with a long run of ducts with a lot of bends and a duct muffler in the attic where the air is dumped, not efficient at all. A speed controler would probably do the same.

I used the street light example to show ballasts can run in the cold, like the op asked, not talking about venting hoods...
 
mountainboy

mountainboy

Well-Known Member
Thanks for all the input everyone. Good example of the street light ballast,should have thought of that. I wasent sure if being cold would effect there efficiency. I was thinking they might have to run at a temp higher then im providing.
I did rearrange the duct work i put a big dip in the middle, like a trap under a sink drain. I then put a small hole in center of trap,so if I do get water it should collect there and drip out the hole. It sure beats having to rearrange my air exchange system.I like running the light in a sealed system,and I wont have to rearrange for seasonal weather changes. I'll try this and hope for the best. Thanks again everyone for your input,I'll check back in if I do end up having any problems.
 
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