High Pressure Sodium Lighting -- Cycling?

[roamerr]

I had a 36 x 40 Garage built and installed a Utilitech brand from Lowes 70 watt HPS (High Pressure Sodium) Light for nighttime lighting. The light has a "dusk to dawn sensor" that cuts it on each night. Light works good except that it cuts off and back on every few hours -- maybe 30 minutes and then again in maybe another hour -- no frequency that is constant. It only takes maybe 20 to 40 seconds to relight to full brightness when it does go out. Is this normal? The light is 28 ft up and I really prefer not to change it unless it is really bad. I purchased this light for the long life and because it was "white bodied" and matched my garage.



Here's the light:
Utilitech at Lowe's: 70-Watt High Pressure Sodium Fixture

 

[firedog]

No, it is not normal to cycle on & off. (30 sec to a minute for restrike is normal, though)
Here are a few things to consider:
1) when the lamp starts to go out, it will cycle on & off. At first with load changes on your system (well pump, A/C, big power users, etc) then more & more on & off without the load changes. However in you case, it sounds like a relatively new installation.

2) light from another source affecting the photo eye.

3) loose connection.

I replaced a mercury vapor light recently with similar issues, turned out to be a broken wire at the auto-transformer, which was a simple fix.

 

[Scooby074]

How old is the light? They cycle when the bulb is dying.

Its possible for reflection to interfere with the eye. Take some black tape, put over the eye and observe for a while. If its reflection a remote PE can be installed where it doesnt see the light until dawn.

 

[sparker133]

It sounds like you might have a bad photo eye. I it is a pole type there will be a twist on photo cell on the top.

If it is a wall pack it will have the photo cell on the inside under the cover.

The other the bulb can be bad and cause it to cycle

The last thing it could be is the ballast kit the light has a ballast and a capcitor. We i go on a service call that is the order i check things. Starting with the cheapest, easiest and most common problems i see with light like that.

If it is the ballast it would be cheaper and faster to buy a new light then replacing the ballast.

1. Test the voltage if ok
2. Test the photo cell tape it off if good
3. Test the bulb replace with new bulb or try in a different fixture if good
4. Ballast or capacitor is bad

hope this helps

 

[Willl]

Make sure the light its self isn't reflecting back into the photo cell.

Quick test would be to wrap/cover the photo cell.

 

[roamerr]

Given that the light is on a tan/white building only 4 foot from the eve and only 1 ft from the siding the reflection can be the issue. I'll check the photo eye.

 

[tallyho8]

That light has a built-in photo eye, not the kind that twist on the top. It is easy to check by covering the eye with a piece of black tape and seeing if the light stays on.

My guess is that it is not the eye. A bad bulb will do that also but I would look for a motor starting issue first. If the voltage to the light is lowered when a motor starts, such as an air compressor, well pump, air conditioner compressor, etc., the light will go off then try to restart.

To diagnose, I would:
1. Tape the eye (if you have access to it) first since this is easiest thing to do.
2. Watch it carefully to see if it goes out when any of your motors start. If it does, you will need to improve your wiring.
3. Change bulbs

 

[firedog]

I just checked out your "lowes" link for the light.
Does yours have a motion sensor as well? That could also be a problem.

 

[roamerr]

The light does not have a motion sensor -- Lowes info is incorrect. Also there has been no motors or other items starting when it goes out. I'm thinking it's the photoeye since the eye is on top pointing up at the white eve. I'll try to check it tommorrow.

I'd like to just block part of the photo eye to make it require more light to go off. It could be the bulb but will be hard for me to find out since I am only around the building a few hours at a time (our home is being built but the garage is complete -- we live 10 miles away now).

 

[Pirate]

Bulb is going bad. Change it. If it stops, that was the problem. If it continues, put in old bulb, keep new one for spare. Change photo cell.