MH Minimum Temp?

[JoshF]

Well, my new propogation set-up is in an uninsulated, unheated garage in Seattle. This means that the temp gets to a maximum of 43 degrees on many days. My 400W MH pendant will NOT fire outdoors, or within 10 minutes of coming indoors. After warming up, it fires fine. Now, obviously AFTER it's going, a low temperature is NOT a problem. I'm assuming the gas in the bulb needs to burn at a certain temperature and not the ballast that is too cool. I imagine putting a small heater in the pendant or near the pendant that would come on for a half hour before the light came on would do the trick, but I have never seen a small heater like this. I want something essentially like a muffin fan, but with a heating coil. Will this work or is there a better way?

Josh

 

[JoshF]

Mitch, you are a genius! Now I feel even worse that I couldn't help out more with those movies for the MACO course! That would work a lot better than some sort of space heater...

Josh

...another trip to Home Depot tomorrow!

 

[Carpentersreef]

How about putting an incandescent bulb or heat lamp close to the MH, set to come on for only 15 or 20 min before you want the MH to fire up, then turn off again when the MH is going?

Mitch

[ January 02, 2002: Message edited by: Carpentersreef ]</p>

 

[Anonymous]

hi.
I am a little surprised by the fact that the bulb won't fire under cold temp... I see MH used outdoor (not as popular as the MV and Sodium, of course), in very cold condition, and they still work fine...

 

[JoshF]

I have to admit that I was more than a little perplexed and worried at first. I bought the light used, online. When it arrived, the bulb fired right away. I then wired it up outside, and the ballast was humming like normal but I only got the tiniest flicker and only just as I shut off the lamp. I thought that maybe I was overloading the circuit, or something else I couldn't even imagine, so I brought the lamp and ballast back inside. I plugged it in and the same thing happened (nothing.) I let it sit for 10-15 minutes and the lamp fired just fine. I'm assuming temperature. It's a 20,000K, 400W bulb. I don't know whether these are more finicky about firing than the industrial MH bulbs, but it sure does seem to be the problem.

Josh

 

[Anonymous]

hi.
I don't know if it has anything to do with your experience, but MH bulb with usual ballast can not be turn on and off without cooling off the bulb first.

The newer ballast used in lux. car can flash a MH bulb on and off, but not the regular industrial/aquarium ballast.

 

[JoshF]

CK: I knew about that. There was a period of an entire day between the initial indoor test firing and the failed firing in the garage. Thanks for double checking, though. There are a million things that I might not know about that would affect this... I certainly didn't know about the temperature correlation.

Josh