Lighting Hood Fan Question

[Entacmaea]

I know this has been discussed before, But I can't find the thread. I have a hood with MH and VHO's with one 4" fan blowing across the water surface. I then have two 2" fans on top of the hood- should these be blowing in, or blowing air out of the hood? One in, and one out? Does it matter?

Thanks for the help!

Peter

 

[Anonymous]

As far as I know the standard practice is to have the fan blowing the hot air out of the hood. Mine works that way. There needs to be an air inlet where room air will be sucked in as the hot air is blown out.

 

[Anonymous]

I had a single fan blowing "out" of my 6" hood. That did nothing to lower the temp. I turned it around and the temp dropped 4 degrees.

I recently upgraded from 4-110W VHO's to 2-175w MH and 2-110w MH. I added another fan blowing "in" and the temp did not increase at all!

So, when it comes to blowing , blow in, not out! :twisted:

 

[Chucker]

:idea: Something to keep in mind..... Any fan blowing out will suck up salt spray, possibly leading to a shorter lifespan of said fan.

 

[Rabbit]

Some people think one fan should blow in, the other out.

Other think all fans should blow in.

I really depends on if your tank is getting too hot or not. I use one fan on my tanks, and have the fan blow across the water. It does cause quicker evaporation, but my tanks stay cool.

Hope it Helps,

D.

PS The Bunny's Back!

 

[Marcosreef]

:idea: Something to keep in mind..... Any fan blowing out will suck up salt spray, possibly leading to a shorter lifespan of said fan.

This is esp. true with Icecap fans. They have an open coil design with holes around the fan motor. Using this fan vented out, will have salt spray getting in the motor.

 

[SPC]

I have mine blowing in. I don't run metal halides and have heard to make sure you don't blow the air directly on them as this will make them less efficient.
One other note, don't forget about the cheap Wall Mart clip on fans for the sump. :wink:
Steve

 

[Anonymous]

Ok, I just did a search on fans because I need to add one myself this year. I found this link in a thread - http://www.nexfan.com/43/132.htm?476

What do you guys think? And how do we wire it?

I ask about the wiring because it seems that the radio shack fans need to be wired as well?

 

[HuBu]

well if there are hole on top of the hood. why dont u just put the fans on the sides blowing in, making the hot air rise out the top of your hood. plus i was told that having a fan blow outward will destroy the fan in time because of the salt in the water vapor. it will ruin the screws in the fan making it worht nothing.

 

[Anonymous]

Originally posted by Tangirl:

Ok, I just did a search on fans because I need to add one myself this year. I found this link in a thread - http://www.nexfan.com/43/132.htm?476

What do you guys think? And how do we wire it?

I'm not fimiliar with that particular fan. I bought a 3 or 4 inch fan from Radio for about 15 bucks. I just cut the female end off an extension cord and spliced it using waterproof wirenuts and wrapped the splices (2) in electrical tape. It's been working fine for over a year and a half.

HTH

Louey

 

[Xphixer2]

Louie, How is the sound level from the fan you bought at radio (shack?)? I bought one too, but just haven't set it up yet.
Tangirl, the fan that is in the link is a 12volt fan for a computer. You would have to figure out a way to supply the 12volts. Possibly a step down transformer. I am also not sure how well it would sense the temp if it was not dirrectly connected to something. It may not be very good at sensing air temp. Love the price though, I am sure it is very silent too. I may look into rigging something up like that. Rich

 

[fishfarmer]

My fan blows in. I have a gap in the back top of my hood for air to escape. My fan blows over the PC's before it gets to the MH because I've read directly blowing on the bulb will shorten lifespan which may have happened to my first bulb.

 

[Marcosreef]

Ok, I just did a search on fans because I need to add one myself this year. I found this link in a thread - http://www.nexfan.com/43/132.htm?476

What do you guys think? And how do we wire it?

I ask about the wiring because it seems that the radio shack fans need to be wired as well?

That fan is way too small. It would probably work good on a nano though!

As far as wiring goes, use a 12 volt AC power adaptor (Radio Shack has these).

Using a 12 volt fan is very good, reduces the "electrocution" danger in the hood. (So they say... :roll: ).

 

[Entacmaea]

Well, sounds like I should turn my small fans around then! Thanks for all the suggestions...

I do have a 6" clip fan going across the sump as well, but I am jsut trying to maximixe cooling as the humidity and heat have arrived here in NY!


Thanks, Peter

 

[Bobzarry]

I have mine blowing in also, and I keep mine on a temp controller to keep it from over cooling, and to make sure it can run independent of the lights, so that on hot summer nights it can still run and keep things cool.



Bob

 

[WayneL]

Well, I guess I'm going against what most people are doing but here is my 2 cents.

My advice is definately out. I had one in and one out as well as none. When I didn't have any fans the temp in my tank was 10 degrees above ambiant. I installed two radio shack 4" fans I ordered of their web site. Now my tank is 1 to 2 degrees above ambiant room temp, I couldn't belive it. Both fans are blowing out.

I did a lot of research on the fans before I purchased them and they seem to come highly recommended by many people. They are very quite as well. You should look for fans in the 30-40 decible level, the ones at radio shack are 38. Also important is the size of the fan. A 3 inch fan at 35 decibles will sound louder than a comperable 4 inch 35 decible fan because of the "type" of sound is makes. I wish I could remember the web site I found that says this but I can't. Anyway, I would recommend both blowing out, they are fairly cheap and very quite so if they only last a year I think the investment is a good one since it definately does the job.

 

[Anonymous]

Originally posted by Xipher2:

Louie, How is the sound level from the fan you bought at radio (shack?)?

They make a hum that is noticeable when they first come on, but it is not all that noticable after it's been on for a while. The sound kind of blends in with the noise of the water flow. The noise is not a problem.

Does anyone make a 3 or 4" fan that doesn't make noise?

 

[Anonymous]

the hood design may be a factor in which way the fans blow. For example, the tops of all my hoods are constructed of wood slats that have an 1" space between them, so it is easy for air to rise out. If I direct the fan out- it is going to be working against that effect; if the fan is directed in it will help it. No contest in this case.

Tan-
The little dc fans require an adaptor- it can be got at home depot- the thing you are looking for is a doorbell transformer- I forgot the real name for it but when I've been to home depot there is only one thing fitting that description. You wire your regular plug to the transformer and the fan to the transformer. I use these little guys for vivariums- some are pretty powerful but not as much as the bigger ac fans.

 

[Marcosreef]

The real name for the door bell transformer is a "Door Bell Transformer"

 

[Anonymous]

Hah- ya but it says something like 120 VAC so and so on it...
Obviously I'm not an electrician.