System Sensor 2WT-B

The System Sensor 2WT-B is a 2-wire smoke and heat detector. Similar to the popular 2W-B smoke detector, the 2WT-B is a member of System Sensor’s i3 Series of photoelectric smoke detectors. The important difference is that the 2WT-B also has an integrated fixed temperature thermal sensor which trips at 135°F (57.2°C). Honeywell does not manufacture their own wired smoke and heat detectors. In fact, System Sensor is a subsidiary of Honeywell. Therefore these detectors are specifically designed to work with the wired Honeywell VISTA panels ranging from residential panels like the VISTA-15P and 20P to larger, commercial grade systems like the VISTA-128BPT and 250BPT.

2-Wire devices are the easiest smoke/heats to install for several reasons. Popular alarm systems like the VISTA-20P support 2-wire smoke detectors on Zone 1 of the system. By default the first zone is configured as a fire detection zone. There are special parameters designed to power and transmit/receive data over the same pair of wires. Also when smoke detectors are tripped they require a power reset to be function again. Zone 1 on these panels automatically resets power to this zone after the alarm canceled by disarming at the keypad. This not only makes wiring much easier but it eliminates the need for an auxiliary power supply.

Before this technology was built into the VISTA panels every smoke detector system required a separate aux power supply, transformer and backup battery in order to power the sensors. In order to reset the devices after they were tripped a relay was required. This meant more hardware and wiring. The 2 wire i3 series smokes are a great option that make it easy for anyone setup a wired smoke detector loop.

*Keep in mind, the i3 series devices require wiring from smoke to smoke in a series loop. Technically they are normally open (NO) devices but there is a special base plate that shares positive power. This results in a single smoke being able to close the circuit. Essentially you have to run wires from device to device in a series loop. Then strap a resistor in parallel at the last smoke for end of line supervision. You can also strap the resistor at the panel but this will not truly supervise the line from cuts. Just trick the panel into thinking it is. We recommend strapping it at the end of line.**

Please note that the System Sensor 2WT-B does not include a built-in sounder. If you want an identical sensor that includes a built-in sounder for alerting building occupants to a fire, then you should consider the System Sensor 2WTA-B instead.

Read here to learn the difference between smoke detectors and smoke alarms. Photoelectric smoke detectors work with an alarm system, and when properly maintained and tested, can last for an indefinite period and do not automatically require replacement after a certain period of time like smoke alarms and CO detectors do.