Title pretty much says it all.
Light & Fan Controller plugged into timer, via industrial extension with multiple outlets. Fan comes on light doesn’t. I will unplug timer and plug it back in and the light comes on. Happened two days in a row now. Ordered backup bulbs, in case bulb was bad (and to have on hand just in case) but wondering now if it might be ballast.
Does anyone have any good troubleshooting tips?
Thanks,
SkyDog
First thing i’d do is try a different timer. The contacts inside the relays can become burned or corroded over time especially if it’s not a heavy duty timer. Think like old cars with points still in the distributor, you had to clean them every so often… I bet the timer is a likely culprit.
What is the load on the timer?
Right now, it just has the inline fan and the light. Worked fine for the first 7 weeks. Changed from MH to HPS a little over a week ago.
I would check the timer like @Jellypowered said. I have had new timers stop working within days of being opened.
I will assume you have 120v power? Generally the small timers are 15 amps. I would look on it to see if it has the amperage. Was the new light you switched to more watts?
When an HPS bulb starts to go bad it will cycle on and then shut down after a short time and repeat. When a MH bulb goes bad it explodes (they make a REALLY loud noise too 
). How old is the bulb?
I have two new timers coming tomorrow or Monday. I ordered them for other things but can use to test. Thanks.
Edit: Just looked at what I have on order and it 's rated: Rating: 115V, 60 Hz, 15A/1725W
Yes, 120v. Timer came as part of my grow tent package so probably cheapy. Will check and see what it says when I get home. Both bulbs 600w.
New bulb. Just been running a week and a half. Once I got it going yesterday it ran all 12 hrs like it was supposed to. I will see if that is the case when I return home this afternoon.
Thanks, ALL, for the replies!
Tech specs on the light shows 5.4 amps. draw 6" inline fan shows .90 amp draw.
That load should be no problem. Hopefully and most likely it is the timer.
Well…It happened again this morning. Fan kicks on at correct time and no light. I pull the timer from the outlet wait a few seconds and plug it back in…nothing! I did this a couple times and then switched outlets on the extension with the fan…nothing! Plugged the ballast directly into the outlet…nothing! (Did each of these three times to be sure) Each time, the fan on the ballast was blowing. I’m eight weeks into a grow right now. This sucks!
Now, in a panic, I pull out the MH bulb and plug it in to the outlet and it comes on…must be the bulb, huh?..Nope! I pulled the plug from the wall and plugged it back into the timer. Plugged the timer into the wall…nothing! Finally on the fifth or sixth try the light came on and stayed on for as long as I was watching.
I’ve got to believe it is the light now, most likely the ballast, but this is the first time I have ever used this kind of light so I can’t be sure. Will call tech support in a few hours, when they open up, and hopefully get this resolved.
I’m open to any other suggestions anyone might have as it is unlikely I will have this resolved until next week some time. What if it won’t come on next time? how can I give the girls some precious light?
Thanks all.
SkyDog
Do you have any spares lying about that you could troubleshoot with?
I generally have an old bulb, past it’s life but still working, that I can test a ballast with. I also always have a spare timer, just in case.
I personally would not run a 600W bulb directly from a timer, timers are notorious for having poor contacts and a HPS light draws power in a different way from most devices which is harder on the contacts of your timer.
If you get a 4 way extension lead and carefully strip some insulation from a couple of inches of the cable, leaving the three wires inside with insulation, then break the live wire and put a relay in there and connect it to the ‘normally open’ contacts then have your timer supply power to the coil when it turns on then you now have a ‘contactor box’ that cost you about £20 and, depending on the relay you use, can switch up to 2.4KW of power.
You can get physically larger relays with a clear case so you can visually inspect the contacts as well.
It may be that the bounce on your timer has affected your ballast or bulb. When a relay switches, the contacts bounce for a bit, turning the power on and off rapidly for a short time. This can sometimes cause issues especially in cheap timers.
But to troubleshoot your problem, I would try the ballast and bulb on their own. If they work fine it suggests the timer is not working. If they do not it does not mean the timer is good though, sometimes a failure in one device can cascade and lead to other failures. Test the timer with something that draws a similar amount of power as well.
If possible try each individual component in isolation from the others, if they all work see what the combination is that makes it fail.
I have had cases where a timer went and took other items with it leading to multiple failures at the same time. If your contacts are on the way out, it is possible that your timer is sending voltage spikes down the line although this is rare.
Just noticed you do not say if your ballast is digital or not. If it is not then it will draw a lot of power to start and even when on, as it is an inductive load, it should be treated as double the rated amperage for timer/relay purposes.
How new is all this kit? Is it under warranty?
If it is, I would take it back to the shop and tell them you need a replacement the same day for obvious reasons. A decent shop will realise how serious your concern is and, if nothing else, supply you with a replacement until it is returned or replaced.
My tests would be, try a different bulb straight to the wall socket, try the timer with an equally demanding device, try a different ballast. You say your light sometimes does not turn on even at the wall socket, is this with both bulbs? If only one it might be your ballast is failing, or just one bulb.
But if in warranty, I would take the ballast, and bulbs to the shop you got them from and get them to test it all. They may well have another ballast to test your bulbs, and other bulbs to test your ballast. Take the timer too and have them test that. That would be the best and quickest solution.
If everything works fine away from your home, test your mains for voltage spikes…
I had the problem with my HPS bulb which had been running fine for a couple weeks when this started. The spare I used this morning was my MH bulb which has about 5 weeks of 18/6 use on it. I will look into using some kind of relay switch whether it be adding one myself or buying one.
I have tried plugging the light in directly to a known good outlet. I did this while the HPS light bulb was still in the fixture. I also had the MH bulb working when I plugged it into the wall the first time, but when I moved it to the timer it took about five tries before the bulb came on again. However, each time I plugged the timer in, the inline fan attached to it came on. I have two more heavy duty digital timers I ordered for other uses that I can try too. Rating: 15A/1750W The digital ballast I have is rated at 5.4A and the fan is 0.9A which should be within the limits of the timer.
Kit was ordered in April and setup for the first time in early May. Place I ordered from is on the west coast and I’m on the east coast so will not be able to visit. Have to try to get this done via delivery.
Going to try your suggested test methods when I return home tonight.
Right now I have two digital timers and two bulbs on the way to my house. I guess another light, hood, and ballast is in my near future to prevent this from happening again…maybe
Things like ballasts place very a heavy inductive load on a timer at startup which then drops as the lamp heats up. The (very) small print that comes with most timer instructions will say not to use with an inductive load 
You can get heavy duty versions which usually last longer but not always. Your best bet is a grow light contactor box (hopefully one with a decent relay inside). You can then use any timer, a cheap digital one will do fine and keep it’s settings when the power goes out.
HPS requires a starter like a fluorescent tube/striplight does.
The MH bulb does not.
I assume this is a MH/HPS switchable ballast if so the starter may have gone bad. it is normally inside the case. DANGER HIGH VOLTAGE
If it does the same thing if you plug it directly in to the wall. I would suspect that to be the issue.
Edit: just seen you tried without the timer.
The ballast is designed for both MH and HPS and is adjustable 250/400/600. I have only ever run it on 600 other than twisting the dial to make sure it was not between settings. I have pulled the timer out of the equation for testing. I tested with an MH and an HPS this last time plugged directly into a wall outlet.
I had the MH plugged into outlet #1 and running. I moved the plug to outlet #2 and the MH did not come back on. I unplugged the light and changed the bulb to HPS and plugged it back in to outlet #2 and the HPS did not come on. I unplugged it and the next time i plugged it in the HPS came on. The store told me they would send me a new ballast.
This morning I went to plug the light in and nothing. This happened another five or six times until it finally came back on.I can hear a faint click in the ballast each time I plug it in and both fans come on.
So for now, I am hoping the new ballast will resolve the situation. Definitely going to go with a relay when I get a chance to take the timer out of the equation for good, Also going to get backup for everything, so no one component, no matter how big or small, can take me out. Can you say Generator…
Thanks for the info!
SkyDog
Don’t know how many timers i went through over the years but it’s a lot. I’ve given up on hps/mh etc after more than 20yrs growing with them. My diy cob and solstrip led rigs have shown me whats possible with a lot less heat generated and less energy consumed 
I guess I can see why you changed. This is just my first grow and I decided to start with something basic to see if I could even get it going. There are definitely a lot of options and I’ve looked seriously at the solostrips.
I want to try to keep something going at all times so I am very interested in having two rooms. One for clone/veg and the other for flower. With that in mind I definitely want another light just as soon as I can afford it.
Thanks for the info!
This says to me that IMO you have dirty contacts in your timer and they are not supplying your sockets with correct power. Your fan will be much less fussy about this than your ballast.
If your ballast and bulbs work fine with a socket when you turn the socket power on and off but not when the timer contacts are used then the problem is in the timer.
If your contacts have corroded then they may only let a certain amount of power through, your fan seems fine but the amps needed by your light might mean that the voltage drops in order to supply the amps required, meaning your light will not spark. Your fan will run, but only when the starter in your ballast is charged enough, in your case about the 5th or 6th try, will it be able to spark your light.
The more I read about this, the more I am thinking that your timer is not strong enough for your light. Even though it may say the words ‘heavy duty’ it may not be up to handling 600W of lights. I have yet to meet an off the shelf timer than can without a contactor box TBH
At this point, apart from getting in spare kit so no failure can slow you down, I would get either a relay or contactor box and a new timer (digital, I have also yet to find a reliable mechanical one) and have the new timer run the contactor box or relay.
I suspect your problems might vanish at this point unless the (suspected to be bad) timer has put voltage spikes or other nasties through your ballast and affected other components.
Another concern, by switching back and forth between MH and HPS, you may increase the chance of unwanted sex organs.