Cmh problems. 2 bulbs blown in a week.

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chronnie49

Well-Known Member
I am having some issues with a 315 cmh light that I've only had for a few months.

I used the philips 942 bulb for 6 weeks during veg without any problems. When I switched to flower I added a 600 watt hps and now I have blown 2 cmh bulbs in a week.

At this point I figure it could be a ballast issue or maybe my contactor. Both lights are plugged into the same contactor but the hps bulb is fine and its rated to run 2000 watts and I am only using 915.

Has anybody had this issue before?
 
Renfro

Renfro

Well-Known Member
For starters, it's not the contactor.

Are the blown bulbs all Philips? You may want to contact them to see if they are from a bad batch number. I have had that happen before.

I also know that CMH bulbs seem harder to start and I think thats what in the end kills them.

Do you have pics of the arc tubes?
 
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chronnie49

Well-Known Member
I had a feeling it wasnt the contactor but its weird this just started happening when I plugged in the hps.

Both bulbs are philips 942. The online shop I bought from is sending me a replacement for the first bulb and I just emailed them this morning about the second.

Heres some pics of the first one.
 

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Mak'er Grow

Well-Known Member
Could it be power surge(s) / brownouts ?
Maybe try starting the CMH lights after the HPS has turned on...setup two timers that are few minutes apart.
 
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chronnie49

Well-Known Member
Mak'er Grow said:
Could it be power surge(s) / brownouts ?
Maybe try starting the CMH lights after the HPS has turned on...setup two timers that are few minutes apart.
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Thats exactly what i was thinking about doing. I have another timer I can use but I am waiting to hear back from the supplier before i try anything else.

I have to wait until the first replacement bulb has arrived anyways since the new bulb blew after 2 days.
 
Renfro

Renfro

Well-Known Member
Inspect shipped bulbs closely. Sometimes they arrive with a hair crack inside and that eventually causes a failure.
 
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chronnie49

Well-Known Member
Renfro said:
Inspect shipped bulbs closely. Sometimes they arrive with a hair crack inside and that eventually causes a failure.
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I inspected both of them very closely. The first one ran for 6 weeks 18 hours a day without any problems then blew 2 days after plugging the hps into the same contactor. The second bulb blew after 2 days as well.

I am hoping to hear back from the supplier tomorrow so I can get this figured out.
 
Renfro

Renfro

Well-Known Member
I had some from nanolux, DE HPS 1kW bulbs. They didn't last 7 months and I contacted the seller and they contacted nanolux and said that the batch my bulbs were bad had issues. They sent new bulbs even after 7 months of use.
 
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chronnie49

Well-Known Member
Renfro said:
I had some from nanolux, DE HPS 1kW bulbs. They didn't last 7 months and I contacted the seller and they contacted nanolux and said that the batch my bulbs were bad had issues. They sent new bulbs even after 7 months of use.
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The online shop I use seems to have good customer service so I hope they will send a replacement for The second bulb too. I will ask them if they are getting a lot of returns on these lately.

Its just weird that the cmh worked fine for 6 weeks then as soon as I add the hps I blow 2 in less than a week.
 
Renfro

Renfro

Well-Known Member
Well like I said, mine worked for 7 months and failed with a crack inside on the little roundish arc tube. So a defect doesn't always fail right away. I am glad they are taking care of you with replacement bulbs, thats a good seller. May I ask who you purchased from?
 
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chronnie49

Well-Known Member
Thats true. I'm hoping its just a bad batch of bulbs so I dont have the send the ballast and hood back for them to check out.

I use Onestop Growshop based in the UK. The light is Maxibright focus connect 315 cmh which I believe is a European brand. I never heard of them living in America but its a popular choice here.
 
Skoal

Skoal

Well-Known Member
Power surges will do it. But I had that happen twice and I left everything off for a few minutes unscrewed the bulb. Popped it back in and it worked. I’m also on an old school 2009 magnetic ballast lol
 
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chronnie49

Well-Known Member
Skoal said:
Power surges will do it. But I had that happen twice and I left everything off for a few minutes unscrewed the bulb. Popped it back in and it worked. I’m also on an old school 2009 magnetic ballast lol
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The hps is also on a magnetic ballast which I know draw quite a bit on startup. That bulb is fine, its just the cmh that have the problem.

I wish it was as easy as taking it out and putting it back in but theres little shards of glass inside so I dont think that will help haha.
 
Renfro

Renfro

Well-Known Member
Some old school HPS ballasts can draw even more current at startup if the capacitor is old and wore out. Depends on how it's wired. Might be a good idea to replace the capacitor, they are cheap.
 
Renfro

Renfro

Well-Known Member
This relates more to HPS and MH and the old school ballasts but it's good info for those that like to repair and trouble shoot them.


Back in the day I had a bunch of NIB ballasts and bulbs that a buddy gave me that his work was throwing away. They were just transformers with caps and ignitors, for replacement use but I just wired them up and ran them to make money to buy good stuff. One was a 1500 watt metal halide, I put it on one of those big parabolic reflectors. Turned out the lamp wasn't meant for base up operation so the bulb didn't last long, maybe a week but it was sure bright while it lasted. I learned a lot about how those old magnetic ballasts work by doing all that. They are easy to fix, even if the transformer burns up you can replace it.
 
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chronnie49

Well-Known Member
Renfro said:
Some old school HPS ballasts can draw even more current at startup if the capacitor is old and wore out. Depends on how it's wired. Might be a good idea to replace the capacitor, they are cheap.
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Thanks for all of the info. The ballast has only been used for 6 months and came with a 25 year warranty so I'd hope nothing is wrong with it yet.

Next run ill be using 2 315 cmh anyways so the hps will just be a backup.

I know you said earlier in the thread it wasn't my contactor which I hope is the case. If i cant use both outlets on it at the same time then it doesnt really do me much good.
 
Renfro

Renfro

Well-Known Member
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chronnie49

Well-Known Member
Renfro said:
A contactor is just a switch thats operated by magnetism. It either turns on or it doesn't. So it's not your issue.

If you want to add a delay on an outlet you can add a second contactor and use a delay on make timer to delay the coil voltage to that contactor say 30 seconds.

ICM Controls ICM102 DOM Timer, 10 Minutes Adjustable, Multicolor: Amazon.com: Industrial & Scientific

ICM Controls ICM102 DOM Timer, 10 Minutes Adjustable, Multicolor: Amazon.com: Industrial & Scientific
www.amazon.com
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Thanks for that.

I guess all I can do is wait and see what the shop has to say. I'll contact philips and see if I got a bad batch. The second bulb said it was made in 2016 so maybe sitting around that long has something to do with it.
 
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chronnie49

Well-Known Member
ToneOZ said:
Its hps theres tha problem
&kidding
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Haha yea I am excited to try all cmh next run. I thought the cmh hps mix would provide a good spectrum but with these problems the cmh has hardly been on at all.

This is why I try to buy from local shops but none of them near me stock the philips bulbs.
 
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