Today Greg emailed me and informed me that:
-My wall lights at Wylam are 175 watt MH wall packs using mercury vapor lamps in a metal halide fixture, but you can not use a metal halide lamp in a mercury vapor fixture.
-Metal Halide puts out a light that has a color temperature that is warmer i.e., the colors look more like they are supposed to. Mercury vapor lamps don’t have that quality, but they put out more lumens (measurable light) and last longer. Regardless, both dim with age and it is a good policy to swap every lamp on both properties every two years.
I was having a problem with my light bulb being blown. Well, I looked at the old bulb which said: "Philips 175wr h39kb-175 usa j2-_2". So I went to the store and purchased a "Sylvania Mercury Vapor 175 ANSI Ballast h39". Which I assumed was the same because the model number of the old was h39 and the ballast of the new was h39.
When I went to install the light it was labeled "Type T or R Metal Halide" which means I did not purchase the correct one. Can I use the other or do you have to use the correct bulb? Also, when I was trying to replace the bulb half the lights started not to work and I blew the fuse. Apparently, something is wrong with the wires in the MH wall pack. I will have to look at that tomorrow.