photocell inquiry

I noticed recently that the outside lights which are controlled by this type of photocell INTERMATIC Photo Eye / Light Sensor Ballast 120V K4021 - eBay (item 300374712999 end time Feb-03-10 12:49:29 PST) seem to be staying on even during quite sufficient daylight hours. As a method of testing it a little, I put shined a flashlight up close at the eye, and the lights did turn off then, so I know that it at least is sensing light. Do these particular types of sensors lose they're operational sensitivity after they get old? Because I was wondering if I were to simply replace it with new one whether the sensitivity will be restored then, or whether it's simply a seasonal thing and because it's winter out and it's a little darker during the day that this particular photocell is keeping the lights on. Like I said, the lights are staying on but it's plenty light enough outside, even though it's winter, so it's a waste of electricity... Also I noticed that on the back of the unit it says "sunlight operation only" and "mount with leads down" and I didn't really understand that. Are the leads supposed to be mounted down and if they're not what difference could that make (mine were anyway) and also what is meant by "sunlight operation only" I don't get it. Thanks anyone for "enlightening" me about this issue (pun intended).

 

It could be the changing of seasons and the different setting and rising locations of the sun. You may have to rotate it somewhat in order to get the right amount of sunlight to operate. I'd move it more to the Northeast to pick up the morning sun. The evening will take care of itself.

 

It doesn't really have a way to rotate it, it's just a cylindrical protrusion sticking out of the cover plate, the unit looks like this from the front Time Switches Photo Controls K4021 1800w 120v: N&F Supply it doesn't really have any kind of swivel or any way to really turn it any other direction than the way it stick out...

 

Sunlight operation indicates if you try to use them with artificial light, you will probably be wasting more electricity than it is worth. It takes a whiter light to activate the photocell efficiently than can be produced artificially. "Leads down" would indicate the refraction within the photocell would be affected if you put it leads up.
Now, as far as the activation anomalies you are experiencing, I would chalk it up to the season, wait until summer and replace it if things didn't return to normal.

 

Well, I don't want the photocell operation to be affected by artificial light (there isn't any artificial light around anyway), so does that mean I should probably have the leads down, or up, I am confused. And if I do have to chalk it up to the season, I hate to wait all the way to the summer to see if things return to normal, as the darn lights will be on 24/7 until then, wasting electricity not to mention the life of the expensive bulbs. Does it sound like I just need to get the leads turned the right way, or maybe just replace this photocell with another like it, or maybe have to replace it with a better (more sensitive or perhaps adjustable) type photocell unit that can actually sense decent daylight and turn the lights off when its already light enough outside?

thanks again

 

I'd make sure the leads are in the proper position, and failing that, it may be time for a new sensor. They go bad, but I'm not saying that is the problem, but it could be.

 

Not certain which way the leads are supposed to be positioned, it says for sunlight operation to make sure the leads are down. So I guess since I don't want the lights to come on when there's sunlight I should mount it with the leads up?

 

No, you want "sunlight" operation as opposed to artificial light, so mount the leads down as indicated. That should give you the right refraction.

 

I suspect the sensitivity of the unit is factory set, in the daylight you can imitate darkness by putting black electrical tape over the eye, if it turns off and turns back on when the tape is removed your done, aside from replacing the unit theres no adjustments, a common method for controlling definite off times is to install a timer, set the timer to turn on during daylight hours and the light will turn on when sunlight goes down, as far as the leads up or down these units are installed in post lights , outdoor areas where water is not completely sealed and may access inside, I would think install down so the water wont sit on top of the wires for any length of time though im sure the lead are sealed its just common sense to have any water run off.

 

I should have mentioned if adding a timer to control the off time is something you want to do, I dont have numbers, but any home depot or supply house sell a intermatic wall switch timer, and simply replaces your existing wall switch.

 

Yeah, I did try the black electrical tape test on the unit, which I've now replaced with an identical one. The old unit did turn on when covered with the tape, then turned back off when the tape was removed (during brightest daylight hours). So it did function but I was uncertain whether its sensitivity may have been reduced due to its age or some other factor since the light would always continue to stay on for most of the daylight hours when it wasn't near dark enough out to need the light to be on. Since the new identical unit functions the same with no change, I realize now I have to chalk up the undesirable "light on" mode during daylight hours to the seasonal winter days being not as bright as the other brighter seasons.
As you point out, the sensitivity of these particular units is non-adjustable. My inquiry here had more to do with whether the sensitivity of these somehow "wears out" over time, but no I don't really think so.
And the "sunlight operation only" statement on the back of the unit apparently has nothing to do with the "mount with leads down" statement, which was confusing me at first because when I read it I interpreted it as "if you want the sunlight to operate this unit, make sure you mount it with the leads pointing down". But no.
As you mention, if I really want to set these lights to turn on/off when I like I'll have to install a timer.
Thanks