MANAGING METAL HALIDE LAMPS
Lamp cycles on-off and goes out before warm-up is complete:
A) bulb is at end-of-life. Replace the bulb.
B) bulb is wrong type for the ballast - bulb/ballast mismatch. Wattages must match, except for slightly different wattage in some cases.
Bulbs change color and do so in unlike ways as they age:
This is normal. But truly radical changes, especially with a noticeable reduction in light output, usually indicate that the bulb is at or near the end of its life. Remove any hid bulb that is rapidly changing or has suddenly made a major change in characteristic.
Metal halide bulbs that turn pink may work another month or two but will fail soon.
Note that ignitors in pulse-start ballasts suffer extra wear if operated without a bulb in place that stays on during operation.
Bulb is flickering and it did not flicker before:
Usually this means the bulb is approaching end of life. If the bulb has been used a lot, this really probably means it is approaching end of life. Replace the bulb.
Bulb explodes:
Extremely rare and usually only from overpowering the bulb via bulb/ballast mismatch, incorrectly wired ballast, or very excessive line voltage.
Lamp life
Lamps are available rated anywhere between 1500 and 6000 hours. Generally the European branded lamps are about 6000 hour lamp life, and the basic Chinese brand anywhere down to 1500 hours. The life of the lamp is however directly proportional to the cost of the lamp.