4WTR-B — System Sensor i3 Series 4-wire combination photoelectric/thermal smoke detector with a fixed 135°F thermal sensor and a Form C auxiliary relay, supplied with its mounting base.
The 4WTR-B suits conventional 4-wire initiating circuits where an auxiliary contact is needed to drive a local function — elevator recall, door holder release, damper or fan shutdown — alongside the detector’s alarm signal. Like the rest of the i3 line it uses a plug-in head on a pre-wirable base, so the base can be wired and the circuit dressed before the head is fitted with a Stop-Drop ’N Lock action. Drift compensation and smoothing algorithms adjust sensitivity automatically to limit nuisance alarms, and a wide-angle dual-color LED reports power-up, normal standby, out-of-sensitivity, alarm and freeze trouble. The mounting base is included with the head.
Specifications
| Type |
Combination photoelectric/thermal smoke detector, 4-wire |
| Relay |
Form C auxiliary relay |
| Thermal sensor |
135°F (57.2°C) fixed |
| Sensitivity |
2.5%/ft nominal, as measured in the UL smoke box |
| Operating voltage |
Nominal 12/24 V non-polarized; minimum 8.5 V; maximum 35 V |
| Maximum ripple voltage |
30% peak to peak of applied voltage |
| Standby current |
50 µA maximum average |
| Maximum alarm current |
35 mA |
| Alarm contact rating |
0.5 A @ 30 V AC/DC |
| Operating temperature range |
32°F to 100°F (0°C to 37.8°C) |
| Freeze trouble |
41°F (5°C) |
| Operating humidity range |
0 to 95% RH non-condensing |
| Input terminals |
14 to 22 AWG, SEMS screws |
| Dimensions (including base) |
5.3 inches (134 mm) diameter x 2.0 inches (51 mm) height |
| Weight (approximate) |
7.1 oz (200 g) |
| Listing |
UL 268, Fire Protection Signaling Systems |
Installation notes
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Narrower temperature range than the standard models: because it carries a thermal sensor, the 4WTR-B is rated 32°F to 100°F (0°C to 37.8°C) — not the 32°F to 120°F of the non-thermal 4W-B. Do not apply it in unconditioned spaces that exceed 100°F.
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Alarm current is higher than the non-relay models: 35 mA maximum, against 20 mA @ 12 V / 23 mA @ 24 V for a 4W-B or 4WT-B. Size the auxiliary power supply and its standby battery on the 35 mA figure.
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Relay contact rating: the auxiliary contacts are rated 0.5 A @ 30 V AC/DC. Loads beyond that require an interposing relay.
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EZ Walk and remote maintenance signalling are 2-wire features: the i3 remote maintenance signal (via the 2W-MOD2 module or an i3-protocol panel) and the EZ Walk loop test are listed for 2-wire i3 detectors. Do not specify them for this 4-wire model.
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Freeze trouble indication: the red LED blinks every 10 seconds at 41°F (5°C), which is a trouble indication and not an alarm.
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Mounting: 3½-inch or 4-inch octagonal back box, single-gang back box, 4-inch square back box with a plaster ring, or direct to the ceiling using drywall anchors.
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LED sequence: at power-up both LEDs blink every 10 seconds; in normal standby the green LED blinks every 5 seconds; out of sensitivity the red LED blinks every 5 seconds; in alarm the red LED is solid.
Related models
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4WT-B — same 4-wire photoelectric/thermal detector without the Form C relay.
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4W-B — 4-wire standard photoelectric detector, no thermal sensor and no relay.
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4WTAR-B — adds an integral sounder to the thermal sensor and Form C relay.
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2WTR-B — the 2-wire equivalent with fixed 135°F thermal sensor and Form C relay.
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4WITAR-B — 4-wire with isolated thermal sensor, sounder and Form C relay, for distinguishing a local from a general alarm.
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SENS-RDR — i3 sensitivity reader; RT removal tool; A77-AB2 retrofit adapter ring.
Specifications taken from the System Sensor document “4WTR-B Smoke Detector Architectural/Engineering Specifications” (May 2009); supporting family detail from the System Sensor data sheet “i3 Series Photoelectric Smoke Detectors,” document A05-0318-007 (6/09), and the Honeywell i3 Series brochure SY-BR-i3Series (February 2022). Manufacturer specifications are subject to change without notice.
