The System Sensor 4WTA-B provides reliable and consistent fire-protection for residential and commercial buildings. It is a 4-wire smoke and heat sensor that also features a built-in 85 dB sounder for alerting those in the building. The device uses photoelectric technology to detect smoke.
Photoelectric technology involves using an internal light that becomes refracted when smoke enters the chamber. This is one of the most consistent and proven methods for reliably detecting smoke. Keep in mind though that this detection method works best in areas free of fine airborne particles, including kitchens, bathrooms and garages.
The fixed temperature hear sensor inside the 4WTA-B activates at 135°F or higher. This is a great second method for ensuring that any fire is properly detected in time. The device also functions as a freeze sensor that causes a trouble condition upon detecting temperatures of 41°F and lower.
With its 85 dB sounder, the 4WTA-B is a step up over its little brother, the 4WT-B. The A in the name actually stands for "annunciator" so that you can differentiate the two devices. Having a sounder is a great feature for any life-safety device, as it makes it more likely that building occupants will be successfully alerted in the event of a fire.
One thing to remember about 4-wire smokes is that they are often more difficult to setup and configure than 2-wire smokes. We recommend DIY users to go with 2-wire smokes instead. But a key advantage with 4-wire smoke detectors is that they can go on any standard hardwired zone. Meanwhile, 2-wire smokes must go on a zone that offers sufficient current and automatically resets after an alarm is cleared. For that reason, 2-wire smokes must go on Zone 1 on a VISTA.
There are various add-ons required to use a 4-wire smoke successfully. The device requires an external power relay that is used for dropping power to the sensor and getting it to stop sounding. An external power supply is also needed if the panel does not provide enough power on its own. Finally, an end of line resistor (EOLR) and an end of line power supervision relay are also required.
Note: This devices measures 5.3" in diameter, and it has a height of 2.0".