Installing Fan in the canopy

[arvin]

I am trying to install fans in a canopy for MH lights.

Should the fan blow out or in? The grill of the fan should be outside or inside?
I have two fans and it is going to be two 250W MH.

Another question I have is that I noticed in Bill's thread that he is going to put his ballasts in a breaker box. Is it necessary and what is the advantage? I have seen some installations where the ballasts are installed in the cabinet or in the wall behind.

TiA.

 

[chase33]

The fans should blow in across the water. I have three fans on a 48" x 24" canopy. Two blow in and one pulls air out. The grills should be on the outside, but if the fans are on the top you may not need to install them. Someone else will have to chime in to answer your ballast question. I have mine installed on the outside rear of my stand.

 

[DaveK]

Fan installation depends upon what you are trying to do. If your goal is to simply cool the MHs, the I'd set them up to blow into the fixture, if I wasn't using glass mounted in the fixture. If you are using glass on the bottom of the fixture then it doesn't make as much difference, but I still prefer to have the fan blow in, because most of the dirt will get trapped on the fan, or you can add a filter to the fan.

If you want to cool the tank then do as chase33 describes, mount the fans so they blow across the water surface.

If mounting fans in the fixture, you should also have and equal amount of venting holes, so air can go in or go out, depending on the direction of the fans. I'm not a fan(no pun intended) of using one fan to move air out of the fixture and another to move air into the fixture. Use venting holes, and have both fans blow in or both fans blow out, you'll double you airflow.

 

[Jcurry@wesketch]

the fans will last longer if they blow into the canopy. Fans drawing air from inside the canopy pull salt laden air across the mechanisms and corrode them. If putting ballasts in an enclosure make sure it it vented to allow the heat to escape. Even electronic ballasts produce heat just not as much as magnetic ones.