Bulbs on fire
 

OK, most of you saw the endcap I posted a while back, and we all blamed the endcap. It's happened again, but this time I got a better idea of what is happening, I think. I believe the bulb is getting hot enough to start melting the endcap, as you can see here, the melted area goes right around the bulb.

http://www.islandreef.ca/post/burnt.jpg

I wonder if there is something wrong with your bulb? I use the coralife end caps and have never had a problem with the VHO on them even though there suposidly for NO tubes.

Steve

Steve, this isn't the same bulb as last time. This is the back bulb. And my house smells so bad right now that I have to leave for a while!!

That is the feeling I have had all the time. It looks as if the bulb is in contact with the endcap. In addition the temperature probably exceeds the rated temperature of the endcap. Hence the melting. :eek:

yup but the temp should be no where near the rated temp for the endcaps.. so I am wondering if the bulb is to fault.

Steve

How old is the bulb Brad?

What type of ballast are you using?

Tony, the bulb(s) were about a year. Only the end got hot. I could hold the bulb anywhere past the first few inches. The endcap couldn't be touched by my bare hand for about 15 minutes after the lights were turned off.

Chris, I'm using a workhorse 7 ballast.

Do you think bulb age could be a factor? A year ... what is the recommended change-out schedule for these. Are they actinics? Isn't that 8-10 months (I ask, feeling suddenly very self-conscious about the 18-month old actinics on my setup :eek: )

Tony, I woulnd't think old bulbs catch on fire.

What if your WH 7 is acting up? I'd have a hard time sleeping if this was happening to my tank.

I did not see the other pics, what type of end caps are they? When I had 3 NO way overdriven, on my 33g, a could not touch the bulbs, but those expensive IceCap encaps never showed any signs of melting, even the rubber is fine.

Lee

Jack, I guess that is a possibility, but I would think both tubes would have a problem. This setup has been as-is for a year+ without a problem, now I get 2 endcaps fried in as many weeks.
Funny thing is the centre of the bulb was fine to touch, but inside the endcap was like touching a MH bulb!! After 15 minutes, I still had to use a rag to undo the endcap.
Lee, they are Icecap ends, and they are rated for 220 degrees. The tube was way hotter than that.

Are you using 2 vhos on 1 workhorse 7 and plugging them in serie?
apparently workhorse 7 can only run one vho bulb
and if u plug them in series they will be overdriven by 20%. and they dont recommend that.

check this out

http://www.aquariumpros.ca/forums/sh...highlight=fire

http://www.aquariumpros.ca/forums/sh...5&pagenumber=1

I thought WH7 was the standard for 2x110w VHO?

I'm guessing youre ballast is broken, you've never had this problem.

series decreases the on/off cycles of the bulb, but I have been doing it for 1.7 years now. using the 4the wire can over drive upto 20%. like I said I have been doing that also for 1.7 years but my measured current increase was only 8%, Also my bulb ends are not to hot to hold.

Brad cut one of the red wires and cap it off and see if you still get to hot with 3 wires.

Steve

Does not an Icecap ballast underdrive the bulbs? Good post from AP. I was reading it there also on the ballast Brad is using and was going to point him there also.

I dont see old bulbs being the problem. Some have run them for years.

Steve, the bulbs are not hot most of the time. I could always touch the tubes and the endcaps. This was a spike of some sort.

I would then ask if there is more than one tube hooked up to that ballast. If so, are there any problems with the other tubes :question:

The ends of the tubes should be warmer than the middle, as the cathode that emits the electrons is located there..

Is the tube still getting extra hot :question: , if so I would simply try another tube in that location. If the new tube does not get hot, I would discard the old tube, and carry on with the motto "don't worry, be happy" :biggrin: :biggrin:

a icecap runs the bulbs at 66% of the rated power.

you have to remember that the post on AP is from a manufacturer that wants to sell ballasts. so they are going to say that you need more than one ballast to run two tubes. makes ecanomical sence. but you have companies that have been running two tubes off there ballasts for years, they are just reproducing a icecap set up. also if you read and you hook up the tubes in series using only 3 red wires the only effect they mention is that you will reduce the amount of start cycles for your tubes. (I have been doing this for almost 2 years and they are still lighting fine.) if you use 4 wires you can overdrive up to 20% but mine tested out at 8%

so running in series using 3 wires is fine by them aside for start cycles.

Steve

Bob, the other tube was fine from tip to tip. The problem bulb was also cool to touch at the opposite end from the end pictured here. So, in a 2 tube setup, only one end of one bulb got this hot. Same thing happened 2 weeks ago with a different tube. I believe that there is something wrong with the ballast and/or wiring. For now, I'll use phillips 40w actinics wired in parallel.

I originally plug them in series(4 wires in one end cap) the ballast was running hot and the end caps also( fingers on it maybe 3-5 sec)

then now i try to do them in parallel (2 in each endcaps and according to fulham is underdriven) and the ballast is still as hot but the endcaps are a bit cooler but it is definately not as bright as in series.

my bulb and ballast are around 3 months


but i just got one question that im worried. since fulham doesnt approved the wiring in series. what if something happens and the insurance wont pay since is not wired accordingly.?

Hey Brad, did you resolve this issue? What was the problem? Do you think maybe the endcaps shift over time and got farther apart and you ended up with arcing on 1 end which made that end of the bulb really really hot?

Sam, I ended up replacing th eVHO tubes with the NO philips tubes, and mywiring was a bit "unconventional", me thinks. I don't think the end caps shifted at all, they seem pretty solid and tight. I really can't recall what was wrong with my wiring, but I did change something.

you only had one pin hooked up out of the two. so it was forcing all your current to use 1/2 the normal path and ended up frying the pin.

Steve