fan blowing onto MH bulb?

[JRF]

Hi,
I havn't received too much response from this question on other boards. So here it is: I have some of the PFO Horz. pendants that have a fan blowing directly onto the MH bulb. I have heard that this is not the best situation, that you should not have a fan blowing directly onto the bulb, but instead, place the fan so that it blows underneath the bulb to carry heat away. If this is true, should I just disable the fan?
Thanks
JRF

[PerryinCA]

Don't disable the fan if you like the color/output as it is. Its not really bad for the lamp per say, but you will get better intensity from a hotter lamp. Just the nature of gas....more heat, more activity.

-Perry
Sunlight Supply, Inc.

[JRF]

Thanks for the reply.
So there would not be a problem if I decide to disable the fan then?
JRF

[ASH]

If there are fluorescent lamps in the same pendant, and they run when the MH does, you need to use the fan. If the ballast is electronic and in the pendant, you need to run the fan.
If it's an open top tank, hanging MH pendant on its own, you don't need it. If it's attached to your canopy and MH only, a fan blowing at the fixture, assuming it has a glass shield, would be better than a fan in the fixture.

Nothing is simple. Explain more about your application and you'll get more or better responses. Your point is well taken though, MH bulbs do better when run as hot as possible.

Andy
IceCap, Inc.

[JRF]

This pendant uses one MH bulb and two 32 watt PC lamps. The PC ballast is inside the pendant. It will be hung over the tank ( no canopy ). Sounds like I need to keep the fan running...
JRF

[traveller7]

If you are worried about blowing on the bulb you could reverse the fan and blow the air out of the enclosure. Typically a reduction in air flow will occur, but it would certainly be better then shutting the fan off.

[JRF]

That's a good idea.
Thanks
JRF