System Sensor 4WTA-B (also written 4WTAB) is a conventional 4-wire i3 series photoelectric smoke detector with a 135°F fixed thermal sensor and a built-in 85 dBA sounder, supplied as a plug-in head with its mounting base included. It suits 4-wire installations that need local audible notification at the detector, such as sleeping rooms, apartments and small tenant spaces.
It takes power from a separate supervised 4-wire circuit and signals alarm through dry initiating contacts, so the panel sees a contact closure rather than a current change. Drift compensation and smoothing algorithms limit nuisance alarms from dust and RF interference, and dual-color LEDs report power-up, standby, out-of-sensitivity, freeze trouble and alarm.
Specifications
| Type |
4-wire photoelectric/thermal with sounder, i3 series |
| Operating voltage |
10 to 35 V |
| Alarm current |
35 mA; 50 µA standby |
| Sound output |
85 dBA temporal tone |
| Sensitivity |
2.5%/ft nominal |
| Thermal sensor |
135°F (57.2°C) fixed |
| Freeze trouble |
41°F (5°C) |
| Operating temperature |
32°F to 100°F; 0 to 95% RH non-condensing |
| Dimensions |
5.3 in. diameter x 2.0 in. height (with base) |
| Weight |
7.1 oz |
| Standard |
UL 268 |
| Mounting |
3-1/2 or 4 in. octagonal, single-gang or 4 in. square box with plaster ring, or direct to ceiling |
Installation notes
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Sounder only, no relay. For an auxiliary Form C relay, use the 4WTAR-B, which draws 50 mA in alarm.
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Budget 35 mA per head on the 4-wire power supply and standby battery.
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Voltage: check voltage drop at the end of long runs against 10 V.
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100°F ceiling: do not install in attics or unconditioned spaces that exceed it.
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Synchronization: with an RRS-MOD module, all i3 sounders activate together and can be silenced from the panel.
Related models
The 4WTR-B is the same 4-wire photoelectric/thermal detector without a sounder (35 mA alarm). The 4WTAR-B adds a relay; the 2WTA-B is the 2-wire version with sounder.
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