Light keeps going off and on? Need some help here!

I have a 1000w HPS that started going off the restarting when the air or heat would kick on. It occationaly happened not always though. It had been getting worse over the last few months. Now today the bulb finally blew. My question was it the bulb causing the problem the whole time and it finally laid down or is it the ballast? My 400w has no issues. I have switched the ballast to different breakers and it does it on both circuits. I thought it might have been a power issue. SOME HELP PLEASE!!!!

most likely the bulb

Only when the air or heat kicks in??

That sounds like it would be a power issue, your air or heat is causing a spike on the breaker and its not leaving enough power to keep your light burning.

Its probably a combination of power issue/light bulb issue.

How old is your ballast, and how long have you been burning that bulb?

I would be careful before assuming its the bulb because if it is a power or ballast issue that is going to cause the bulb to burn out Sooner.

Both are a few years old. I kinda expected the bulb to go anytime. I did notice that it was kicking off with out the heat/air the last week or so. Maybe it was getting a little worse.

id just sell the ballast and get 2 400watts or something it sounds like the power as bctrippin said so it would be a expensive problem to fix u would have to run a new wire to the board and put it into a new circuite breaker so prob a $500 job

sorry just read ur last post sounds like the ballast. get a new one and if it still happens then u will have to run a new wire

yea u should test a new bulb and find out

smokeandfly said:

id just sell the ballast and get 2 400watts or something it sounds like the power as bctrippin said so it would be a expensive problem to fix u would have to run a new wire to the board and put it into a new circuite breaker so prob a $500 job

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Yeah it sounds like its not blowing the breaker, you dont want to just replace a ballast with smaller ballasts if its a bigger problem there, that could end up causing a fire.

Unfortunately I think the most important thing to do is determine whether its the ballast, or your electrical system, which can be rather pricey to fix, and noone likes bringing people to their grow house to fix stuff.


How old is your breaker panel? why do I have a feeling you might be on an older system?

o forgot it wasnt tripping the breaker i wouldnt think it would be his circuite then actualy cause it would burn out and start a fire not just turn off the ballast. id say it was the ballast for sure now.

smokeandfly said:

o forgot it wasnt tripping the breaker i wouldnt think it would be his circuite then actualy cause it would burn out and start a fire not just turn off the ballast. id say it was the ballast for sure now.

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Well yes and no. It COULD cause a fire, but the ballast started restarting when his heat/ fans came on, at first it may have been the fact that while other stuff started, it was not leaving enough power to continue to burn the 1000w bulb.

Over time, if a ballast is being restarted like this it is going to cause the ballast to break down Much, Much, Much faster.

But he also said he tried switching the breakers, and it didnt really help much.

IMO there could be two reasons for this 1. It is the ballat, whether it has always been the ballast or has broken down over time 2. Even on a seperate breaker, an older electrical system will be more susceptible to power spikes over all the breakers, so even a spike on a different breaker might casue all the lights in your house to flicker, or in this case cut out the ballast.

The fact that there Hasnt been a fire so far does NOT rule out an electrical system issue.

If its an older system I would be a little more concerned, but if you do have a newer electical system, there is a much better chance that it is just a ballast issue.

thats why i say its the ballast as the start up amperage is alot higher than alot of other start up amperages so it doesnt make sense that it can keep starting up when theres alot of power being already used. if u get what i mean. sorry im only a apprentice sparky so dont know the full ins and outs of it all but do know abit

The ballast is working exactly as it's supposed to. It has a thermal breaker that trips when it gets too hot, and that feature is working to protect the ballast.

Old bulbs before they die create a heavier than normal load on the ballast and that's why it heats up and turns off. Don't sell the ballast, all you need is a new bulb.

If the new bulb makes it trip then you just need a fan on the ballast NOT A NEW BALLAST.

meh if i needed a new fan on a ballast id buy a new ballast lol. but never new that before good to know incase mine start doing that.

Smokeandfly you don't understand how magnetic ballasts work.

They all get hot, period, and if you put a fan on them they run cooler. When they run cooler they run more efficiently and it's a significant increase in lumens per watt when run cool. This applies to any mag ballast and doesn't indicate a deficiency with the ballast that's just how they work.

Mag ballasts can last 20 years or more even the cheapest kit, provided you haven't put the ballast in a place where there's insuficient airflow to cool it.

You could go buy a new ballast if you like, but if you stuck the old bulb in a new ballast it would do the same thing if the new ballast also had thermal protection bult in.

You can tell when you need to replace a magnetic ballast for real when the wiring on the transformer starts to degrade and flakes apart when you touch it.

true thanks for that. didnt know that so u dont mean put a small inbuilt fan in it u mean like a fan putting air over it? i thought u meant rip it appart and put in a new fan as in if laptop fans go they over heat and turn off.

I mean just put a fan blowing on it externally. Could be any type of fan, even a little 80mm computer fan running 12v off a wall wart or just stick the ballast in a place where it gets air blown on it from the fan that you use to blow the plants.

Anything you do to keep any mag ballast cool while running is a good thing and will reward you with less power draw and thus more lumens per watt.

so if i have my oscillating fan hitting them a little bit every time it spins around it would help?

OregonMeds said:

The ballast is working exactly as it's supposed to. It has a thermal breaker that trips when it gets too hot, and that feature is working to protect the ballast.

Old bulbs before they die create a heavier than normal load on the ballast and that's why it heats up and turns off. Don't sell the ballast, all you need is a new bulb.

If the new bulb makes it trip then you just need a fan on the ballast NOT A NEW BALLAST.

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This is assuming he has a ballast With a thermal breaker, which is quite rare on older/cheaper ballasts, which most of us use. And also assuming that he has no fan on his ballasts.

If you actually read the first post it started happening when other stuff was coming on, heat and fans, both can cause large spikes. Over time this could have damaged the bulb to the point where the bulb was also causing issues, then it died like he said. Restarting your ballast and trying to refire the bulb without letting the bulb properly cool it is the absolute worst thing you can do to your bulbs.

The real question is why did the ballast start restarting in the first place.


And although a magnetic ballast may run 20 years like you say. I would Never Ever Ever Ever say to anyone that it can be run until the wires start to corrode. Thats a fire hazard, when properly maintained any ballast can be used for a long time, but theres a lot more to it than putting a fan on your ballast.

There's not a lot to it, mag ballasts are really really really simple.
It's a transformer and an ignitor and some wires and that's it. Transformers are just wires wound around an iron core, so the only things that can go wrong with them is that the insulation on the transformer wires breaks down or the ignitor fails. There's plenty of time between when the insulation starts to flake and when there would truly be a fire hazard, and since his does have thermal protection it can't start a fire period.

Even those that don't come with thermal protection would blow the fuse or trip a breaker when the windings on the transformer actually shorted. True they don't all have thermal breakers, mine do, but they all have a fuse.

I'm an electronics tech and I work on vintage equipment on occasion some of which is 30-50 years old, all of which use mag transformers. I'm not just some backyard hacker I really do know this stuff.

Also you're always supposed to put any ballasts on fire proof material anyway. And you're always supposed to put a fan on your ballasts, it's standard practice.

If you didn't then _you're the risk of fire_ not the ballast. Just set them on a piece of drywall or a big brick or similar and not close enough to plastic or other flammable stuff to set those off. Yes an oscillating fan hitting the ballast with each sweep is fine, not IDEAL but fine. They just should not be sitting in a spot where there is no airflow at all. It doesn't matter so much with little lights like those 150's if you guys are reading this, no I'm not saying you need to remote mount and put a fan on those but 250w and up you guys would all benefit if you had some constant airflow on your ballasts.


No fire ever if mounted right, but that's all up to you guys.

My resistance to buying a new ballast is both saving wasting money and that more often than not older equipment is more robust and better built than new stuff. Replacing an old ballast that's still good could actually be a downgrade.

Good info thanks. I do run a small 4" fan blowing into the heat vents on the side of the ballast. The ballast is always cool to touch this way. Im running it on a breaker that has a ceiling fan and to cfl 23w bulbs. Thats all that is pulling on that circuit. I am assuming there must always be a minimal amount of pull across all curcuits when the heat kicks on. I figured that was just enough to kick the ballast off. I have a 1978 built home with a standard breaker type box. The bulb is a few years old and im not sure but might be 3 or 4 years old and is always working. I wondered if the transformer needed to be turned up on the pole. The lights some times will flicker when the heat comes on. Again it didnt always kill the ballast just sometimes and over the last week or so it was doing it with out a power draw. This shed any new light?