---
product_id: 8984151
title: "System Sensor 4WT-B 4-wire, photoelectric i3 smoke detector with a 135 Degree fixed thermal sensor"
brand: "system sensor"
price: "20020 kr"
currency: ISK
in_stock: true
reviews_count: 8
category: "System Sensor"
url: https://www.desertcart.is/products/8984151-system-sensor-4wt-b-4-wire-photoelectric-i3-smoke-detector
store_origin: IS
region: Iceland
---

# 12/24 VDC four-wire power 135°F fixed thermal sensor Red LED visual alert System Sensor 4WT-B 4-wire, photoelectric i3 smoke detector with a 135 Degree fixed thermal sensor

**Brand:** system sensor
**Price:** 20020 kr
**Availability:** ✅ In Stock

## Summary

> 🚨 Stay ahead of danger with smart, seamless smoke detection!

## Quick Answers

- **What is this?** System Sensor 4WT-B 4-wire, photoelectric i3 smoke detector with a 135 Degree fixed thermal sensor by system sensor
- **How much does it cost?** 20020 kr with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.is](https://www.desertcart.is/products/8984151-system-sensor-4wt-b-4-wire-photoelectric-i3-smoke-detector)

## Best For

- system sensor enthusiasts

## Why This Product

- Trusted system sensor brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Trusted & Certified:** UL and CSFM certified, proudly made in the USA for uncompromising quality and compliance.
- • **Seamless Power Setup:** Four-wire 12/24 VDC connection supports stable, continuous power without battery dependency.
- • **Maintenance Made Easy:** Removable detector cover and built-in remote maintenance signaling streamline upkeep and monitoring.
- • **Precision Fire Detection:** Photoelectric sensor with advanced drift compensation ensures early and reliable smoke detection.
- • **Thermal Sensor Integration:** 135°F fixed thermal sensor adds an extra layer of heat detection for comprehensive safety.

## Overview

The System Sensor 4WT-B is a professional-grade, four-wire photoelectric smoke detector featuring a 135°F fixed thermal sensor for enhanced fire detection. Powered by 12/24 VDC, it offers a red LED visual alert and advanced drift compensation technology. Designed for easy maintenance with a removable cover and remote signaling, this UL and CSFM certified device is a reliable, US-made solution for modern fire safety systems.

## Description

Smoke Alarm, Detection Method Photoelectric, No Interconnection Capability, Power Source 12/24 VDC, Four-Wire, Visual Alert Red LED, Diameter 5-19/64 In., Height 2 In., Digital Readout No, Battery Backup No, Features Removable Detector Cover and Chamber, Built-In Remote Maintenance Signaling, Drift Compensation and Smoothing Algorithms, Thermal Sensor, Hush Button No, Locking Pin No, Operating Temp. 32 Degrees to 120 Degrees F, Standards UL, CSFM, Includes Base

Review: Perfect swap- No issues - Exact replacement for my unit. Left original base plate and added new sensor. Alarm system recognized and all is working.
Review: Installation of System Sensor 4 WT-B - Perfect replacement for System Sensor model # 2112/24TS 4-wire PhotoElectronic smoke detector. Easily removed old unit and rewired the new unit by connecting red wire to + in terminal, single black wire to - in/out terminal, two black wires to no terminal and green and white wires to com terminal. Tested the newly installed unit by inserting allen wrench into recessed test switch and applied heat from a hair dryer. Both test sounded the alarm. Unit is correctly wired and installed when the green LED light is blinking.

## Features

- Smoke Alarm
- Country of manufacture: United States

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B0015QE0HM |
| Alarm | Visual |
| Best Sellers Rank | #122,881 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #129 in Smoke Detectors & Fire Alarms |
| Brand | System Sensor |
| Color | White |
| Date First Available | March 10, 2008 |
| Is Discontinued By Manufacturer | No |
| Item Weight | 8.2 ounces |
| Item model number | 4WT-B |
| Manufacturer | System Sensor |
| Number of Items | 1 |
| Power Source | Corded Electric |
| Product Dimensions | 2.4"D x 5.7"W x 5.7"H |
| Sensor Type | Photoelectric |
| Style | Smoke Detector |
| UPC | 783863017629 |
| Upper Temperature Rating | 135 Degrees Fahrenheit |

## Product Details

- **Alarm:** Visual
- **Brand:** System Sensor
- **Color:** White
- **Item Weight:** 0.51 Pounds
- **Number of Items:** 1
- **Power Source:** Corded Electric
- **Product Dimensions:** 2.4"D x 5.7"W x 5.7"H
- **Sensor Type:** Photoelectric
- **Style:** Smoke Detector
- **Upper Temperature Rating:** 135 Degrees Fahrenheit

## Images

![System Sensor 4WT-B 4-wire, photoelectric i3 smoke detector with a 135 Degree fixed thermal sensor - Image 1](https://m.media-amazon.com/images/I/41TZQsLVDtL.jpg)

## Questions & Answers

**Q: Es necesario colocar una base? el sistema estará conectado al sistema de alarmas**
A: Hello,
Please submit your question in English.

**Q: Is this the update to replace model 2412?**
A: i never used 2412 unit but 4wt-b-4 should work as a replacement it is 12vdc & 2 wires to trigger alarm

**Q: I have an old unit that needs replacing. There is a 4 wire phone cord like coming out of the cieling....red/black/green and yellow, Will this work?**
A: Check the website for System Sensor to check the replacement for the original unit.

**Q: Will this mount onto a standard round ceiling box?  saw a review/complaint about detector having no base.  i'm just replacing a bad esl smoke detector**
A: It comes with new round plastic base plates in the box, but I just used the old ones that were already installed.  So I just twist-locked the new sensor into the old plastic base plate.  If the light does not come up green after installing, try resetting your whole system.  My alarm contractor had to install a resistor or something to get all the sensors to switch to green.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Perfect swap- No issues
*by B***Y on June 26, 2025*

Exact replacement for my unit. Left original base plate and added new sensor. Alarm system recognized and all is working.

### ⭐⭐⭐⭐⭐ Installation of System Sensor 4 WT-B
*by A***R on August 11, 2025*

Perfect replacement for System Sensor model # 2112/24TS 4-wire PhotoElectronic smoke detector. Easily removed old unit and rewired the new unit by connecting red wire to + in terminal, single black wire to - in/out terminal, two black wires to no terminal and green and white wires to com terminal. Tested the newly installed unit by inserting allen wrench into recessed test switch and applied heat from a hair dryer. Both test sounded the alarm. Unit is correctly wired and installed when the green LED light is blinking.

### ⭐⭐⭐⭐⭐ Great replacement for a 4 wire smoke detector
*by M***E on November 4, 2025*

Replaced an older 4 wire smoke detector that had yellowed over time. Works perfectly and has the added capability of fixed rate heat detection.

## Frequently Bought Together

- System Sensor 4WT-B 4-wire, photoelectric i3 smoke detector with a 135 Degree fixed thermal sensor
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*Product available on Desertcart Iceland*
*Store origin: IS*
*Last updated: 2026-03-15*