Photo Control Replacement Chart:
Precision Model T15
ALR AT-15 or PT-15
Intermatic K4121
Tork 2101

LED products work very well with electrical controls such as dusk-to-dawn sensors, daylight harvesting controls, timers, etc. On the other hand, a compact fluorescent (CFL) requires a non-electronic, or mechanical control. The problem using any control device with CFLs is voltage leak. Some photo controls actually leak a small amount of electrical current in the off position. The best way to test if your existing photocell is compatible with CFLs is to measure the voltage at the socket when the sun is shining brightly - a digital meter is required. The voltage should be 0.0VAC. When you see any other reading, it is possible that it is not compatible. The full line of Precision photo control sensors are confirmed through extensive field use and in-house testing to be 100% compatible with all forms of outdoor lighting.

A perfect replacement wall pack dusk-to-dawn photocell, flood light stem mount photocell or pole light photo sensor in applications where you are using HID, Induction, LED or CFL outdoor lighting systems, the Precision T-15 120VAC dusk-to-dawn photocell offers you a wide range of applications as it is designed to fit into compatible light fixtures or a standard outlet box or wall pack. They are equipped with a 1/2" - 14 thread that fits a 1/2" knock-out. The washer and lock nut are included. Mount this photocell sensor in an approved FS box, weatherproof box or fixture. They turn on in the evening when light levels reach 1-3 footcandles and turn off in the morning when light level readings reach 1-5 footcandles. The 6" lead wires are color coded black, red and white and the physical dimensions of the T-15 120V dusk-to-dawn stem mount photocell are 2 high by 1 1/2 wide by 1 deep. They carry a 5 year warranty and are gray in color.

Tips To Optimize Photocell Performance

Do not face the photocell into the midday sun. If the photo control is installed on the south side of a building, face the photocell east or west or point the photo control down toward the ground. The best direction to face the photo control is north.

Do not face the photocell where it can see artificial light. Light from windows, signs, street lights, etc., will cause the photo control not to switch on. The photo control should not be positioned so that it sees the light it is controlling (or reflected light - like off of your white siding or white painted soffit overhang). These conditions will cause the light to cycle on and off.

Do not install the photo control with wires up unless there is NO POSSIBILITY of water entering the photo control around the wires. The photo control must be installed in an approved weatherproof box. Do not attempt to caulk around the wires. Installing a Photocell below the box is WRONG! Photocells installed on top of the Box is RIGHT! Any Photo Control installed by the side of the weatherproof box is: ACCEPTABLE!

When you are testing the photocell, be sure to turn on the power (load will come on) and wait up to 5 minutes for the photocell to switch load off. For further testing cover the photo control completely with black tape or another dark material to simulate night conditions. If you can't cover the control with tape, try covering the photo control with the shipping carton to simulate night conditions.

Precision Direct Wire Photocell Sensor Specification Sheet