Remote Photocell

[Becmar]

A search of "photocell" did not yield the info I wanted. Using a Vista transformer with a remote photocell, the lighting does not activate until near total darkness. This is in spite of the fact that the photocell is in an already dark area. Is there any good long-lasting way to get the photocell to turn on the lighting fifteen minutes or so earlier?

[lfalting]

Are you using the Vista button photocell or are you using the full size? The only way that I know of some what regulating the button type is to tape up part of the eye, this is not very scienitific, but trying to regulate any photocell is a hit and miss type thing. I had previously run into the opposite problem on a system that someone else had install, in that the photocell never went off, the contractor had installed the transformer in a dark location and the cell was mounted on the transformer. I had to convert this to a remote so that the customers lights would operate properly. You will find that no two photcells ever operate at the same times.

[sitelights]

Vista's web site Accessories page has illustrations of two photocell types: remote (swivel arm) and chassis mount (button). The remote FPC 150 is clearly sourced from Intermatic; these things are of very poor quality. We used them for about a year 15 years ago and the premature failure rate was 100%. Our techs are instructed to replace any Intermatics found whether they work or not.

What you have is Intermatic's K4221 and the specs are a bit vague: "Photocontrol shall be 100% factory tested for function within specified light levels." The "specified light levels" are not stated. Your unit may be out of spec; this could be tested with a light meter if the spec was given. A typical turn on spec would be in the range of 1 to 3 footcandles. These units fail "on" and, if you notice, many of the photocontrolled lights you see are on in daylight

Late turn-on can be caused by improper orientation of the "eye" i.e. aimed at the western sky or into the sunset. The proper orientation is to the north sky; the "eye" (of any type or brand) should never get direct sunlight. The K4221 is a "thermal" type so even if the "eye" is not pointed toward the setting sun, the warmer it is the later it will turn on. Note also that the K4221 has a built in delay circuit that prevents the lights from cycling on-off if the "eye" sees car headlights, etc. This delay could also be out of spec.

I would exchange the photocontrol for another brand; the swivel type we use is from ALR. The button types are preferred since they do not have a delay circuit and are fast-acting (15 seconds typically). It can take up to 10 minutes for K4221 (and others) to turn on when the slide is over the "eye" or when covered with black electrician's tape. That's 10 minutes of standing around whistling before the system can be serviced.

[Becmar]

Just for clarification, the romote photocell is the small button type. In the three particular cases, they are all in areas shielded from direct sunlight. I will look for sourcing of a different brand.

Thanks.