[ksfireman]

I just picked up a 250w Metal Halide Pendant for free from where I work but am having a problem with it. My boss told me that the bulb was old and needs replaced, however once I got the light home and plugged it in it worked just fine. The problem started about 5 minutes after the light was turned on. The light will stay lit for about 2 or 3 minutes, then it turns off for about 5 minutes and comes back on and goes through this routine over and over again. My question is this... would an old bulb cause this, or would it be a ballast problem? The ballast doesn't seem to be getting warm at all, so that leads me to believe it is a problem with the bulb. Any ideas or help would be greatly appreciated.

Thanks,

Bradd

[SKRIZ]

have you checked the wiring in the ballast? seems like a ballast issue rather than a bulb issue.

[ksfireman]

not the wiring inside the ballast...but I did check it from the ballast to the bulb and all of that is correct. Not sure what else to try.


Thanks,

Bradd

[ksfireman]

I wonder if it would be the ignitor or just the ballast in general. Any ideas?

Thanks,

Bradd

[The Grim Reefer]

That could be a bad lamp. Any other reefers in the area you could bum an old lamp from? Hit the LFS and see if they have one that is worn out you could try. If it is a magnetic ballast I doubt that is the problem but never say never.

[ksfireman]

There is a club in Wichita Kansas, or at least a forum for one, but I can't remember the website address. The lfs where I am working doesn't have any bulbs that would work...at least not any 250w..they have some 175 though.

Not sure what else to try.


Bradd

[ksfireman]

Well, after some trial and error I got the problem resolved. Just out of sure curiosity I picked up a Ushio 175w 10k and a Ushio 175w 20k bulb from work to see if they would work. To my suprise both bulbs lit up and worked perfectly. I didn't think that you could run anything other than a 250w bulb on a 250w ballast, but they have been working now for about a week.
I just wanted to say thanks to everyone for all of the help.

Bradd

[The Grim Reefer]

Have you checked the numbers on the ballasts to make sure they are 250 watts and not 175's?

[ksfireman]

Yeah, I did check and it is a 250w ballast. Not sure what the deal is, but it is working just fine. I am just glad to get it working right.

Bradd

[golfish]

Probably not a good idea to run a 175 watt bulb on a 250 watt ballast. I know all the MH ballast we use at work run an 277 volt (I think its 277) its not your normal house voltage. The ballast are the same (M58 and M59) their just wired to run on higher voltage because its cheaper.

[ksfireman]

Yeah, that is what I was figuring. I need to pick up a 250w 20k bulb from somewhere here soon. I was just glad to find out it wasn't the ballast that was bad.

Bradd

[Ninong]

I just want to agree with those who are advising that it is a bad idea to run a 175w lamp on a 250w ballast. This is a VERY bad idea. It could cause the lamp to explode and if you don't have a shield under it, you would end up with glass shards in your aquarium.

Glad to see that you will be changing the lamp to a 250w.

[ksfireman]

Since reading this post I have discontinued using the 175w bulb. I will just not use this setup until I can get out and get a 250w bulb. The last thing I want is for something to happen to the tank.

Bradd