Metal Halide Life Expectency

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sfav8r

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San Francisco Bay Area
I just did a service call where one of the 20 lights stopped operating in a parking lot. I normally don't do this type of work, but it turned out to be a simple bulb replacement, but in the process of replacing the bulb, I read the documentation and it suggested that this type of bulb should be changed at/near it's expected life cycle.

It would obviously be cheaper to change all of the bulbs at once rather than having 20 service calls, but I can't reliably determine how long the bulbs have been in service.

My recommendation was going to be to see if another bulb fails in the next month or two and if so, replace all the remaining bulbs at that time.

Does this sound reasonable? I don't want to waste the clients money by changing perfectly good bulbs, but I also don't want to keep dinging them for service calls.

The bulbs are Phillips ED28 175W

Thanks!

Rod

[ February 05, 2005, 11:47 PM: Message edited by: sfav8r ]
 
Re: Metal Halide Life Expectency

Most Metal Halide lamp's will cycle when they are close to going out. they will start to turn off and on and this will shorten the life of the ballest. Tell your customers to call when they start doing this. Most should give about 2 years of service when used every night from dusk till dawn. There are newer systems called pulse start that are expected to last about 5 years and use less energy for the given wattage.
 
Re: Metal Halide Life Expectency

Originally posted by sfav8r:
The bulbs are Phillips ED28 175W

Rod
Click to expand...
This lamp is rated for about a 10,000 hour life. The pulse-start lamps are rated about 15,000 to 20,000 hour life.
 
Re: Metal Halide Life Expectency

It would obviously be cheaper to change all of the bulbs at once rather than having 20 service calls, but I can't reliably determine how long the bulbs have been in service.

Even if you did replace all of them at the same time they will never all fail at the same time so you are back to square 1.

What you could do is replace all of them then keep track of when they fail in relation to their rated life. If only a few fail early replace them individually. Then when failure numbers start to increase replace them all.

-Hal
 
Re: Metal Halide Life Expectency

A good reason to replace them, even if they are a few years old, is their steadily declining light output as they get older, due to arc tube blackening and leakage.

The customer is paying for 175 watts (not counting ballast losses) of light, but not getting it after several years of use.

The pulse starts have improved this situation quite a bit but there are still vast numbers of the old ones out there, and old style ones still being installed every day.
 
Re: Metal Halide Life Expectency

We have mailing labels printed up where we write in the 1. number of lamps we changed 2. number of ballast changed 3. The date

They are universal so they can be used for Layin fixtures, wrap arounds, HPS or MH fixtures.

They help with determining when the fixture was serviced last. It also puts this information on-site and you wont have to go back to the office to dig thru paperwork.
 
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