Agni Response Indicator Concealed 503 | Dual LED Fire Alarm Indicator

Agni Instruments Engineers India Private Limited manufactures a dual-LED 503 response indicator compatible with both conventional and addressable fire alarm detectors. Built with a durable sheet-metal body for wall mounting, it connects directly to the detector base and provides a clear, bright red visual indication when the detector goes into alarm, ensuring fast and reliable identification of the alarm source.

User Manual

Data Sheet

Certification

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Description

Agni -503 Response Indicator Concealed or  Flush mount  is a dual-LED remote visual device designed to duplicate a fire detector’s alarm LED at an accessible and clearly visible location when the detector itself is installed in concealed or obstructed areas. It is especially beneficial for installations in high-depth or false ceilings, air-conditioning ducts, outside rooms, laboratories, stores, cabins, and other restricted or visually blocked locations. By providing a remote visual alarm indication, the device helps reduce response time during fire events and supports efficient maintenance, inspection, and emergency intervention.

Agni -503 Response Indicator Concealed or  Flush compliance  with EN 54-5-7, NFPA-72, IS 2189, NBC, standard  and is tested by NABL and ERTL laboratories. It also conforms to Government of India CPWD DSR specifications, making it suitable for regulated, certified, and government fire safety projects.

The response indicator is assembled inside a robust sheet-metal enclosure that protects the internal electronic circuitry from environmental and mechanical damage. The enclosure is manufactured from CRCA sheet metal using a precision sheet metal forming process, ensuring correct bends, accurate dimensions, and uniform build quality. This construction provides long-term durability and reliable performance in demanding installation environments. 

The device supports surface or flush mounting based on site requirements and delivers clear status indication for faster  smoke detection alarm identification .Manufactured by Agni instruments engineers India private limited., this dual-LED response indicator is designed compatible with conventional and addressable fire alarm detectors. It connects directly to the detector base and provides a clear visual indication during alarm conditions. The dual LEDs enhance visibility, allowing operators and emergency personnel to quickly understand alarm status. The product is widely used in commercial buildings, industrial facilities, data centers, hospitals, hotels, warehouses, and other critical safety environments.

How it Works

How does the Response Indicator Concealed 503 Work?

The Response Indicator Concealed 503 acts as a remote visual extension of a fire detector’s alarm LED, ensuring that alarm activation is clearly visible even when the detector itself is hidden or obstructed.

Commonly Used

  • False Ceiling in Office Buildings
  • Air-Conditioning Duct Detection 
  • Server Rooms & Data Centers 
  • Hospitals & Laboratories
  • Warehouses & Industrial Facilities

Step-by-Step Response Indicator Working Principle?

01

Direct Connection to Detector Base

The response indicator is electrically connected to the fire detector base using a standard 1.5 sq. mm cable.

02

Normal Operating Condition

Under normal conditions, the indicator remains inactive while continuously monitoring the detector’s alarm output circuit.

03

Detector Alarm Activation

When the connected fire detector senses fire and enters an alarm condition, it immediately sends a signal to the response indicator.

04

Dual LED Visual Indication

The Response Indicator Concealed 503 instantly illuminates high-bright red dual LEDs with a wide viewing angle, clearly indicating the alarm location.

05

Remote Visibility in Concealed Areas

Even if the detector is located above false ceilings or inside ducts, the response indicator provides a clear, visible alert at an accessible location.

06

Low Power, Continuous Reliability

The indicator operates on 15-40 VDC and consumes ultra-low power, ensuring dependable operation without overloading the fire alarm system.

Technical Specification

PARAMETER

Specification

Product Type

Response Indicator (Concealed OR Flush Mount)

Model

503

Operating Volatage 

15 VDC - 40 VDC

Average Current 

7.27 mA @ 24 VDC

LED Type 

Dual LED

LED Color

Red (In Case Of Fire) 

Viewing Angle 

Wide Viewing Angle 

Operating Temperature 

-10°C to +90°C (No Icing)

Maximum Humidity

95% RH (Non-Condensing)

Cable Size

1.5 sq. mm

Mounting Type 

Flush Mount 

Enclosure Type 

Rugged / Industrial Design 

Body Material

CRCA Mild Steel

Body Color 

RAL-9010 White Coating 

Dimensions (H × W × D)

80 × 58 × 48 mm

Weight

250 g

IP Rating 

IP 42 (Overall Protection)

Power Consumption

Ultra Low Power

LED Life Span

Up to 100,000 Hours

Design Profile

Low Profile Design

Immunity 

Advanced Immunity to Airborne Contaminants

Standards Compliance

EN 54-5-7, IS 2189, NFPA-72

LAB TEST 

ERTL / NABL

Application

Fire Alarm Remote Visual Indication

Standards & Guidelines : According to IS 2189 / NBC / NFPA-72 should be installed on the outside of the room, cabinet, or directly below the false ceiling to ensure visibility. it is recommended to fit indicators external to the doors to indicate if a detector within that room has operated.

Job to be Done

Primary Job

When a fire detector is installed in a concealed or visually obstructed location, the Response Indicator Concealed 503 helps users see immediately which detector has gone into alarm, without opening ceilings, ducts, or restricted areas.

Safety Job

Ensures visible fire alarm indication for concealed detectors, reduces response time, aids safe evacuation, supports maintenance, improves emergency coordination, and enhances compliance in buildings where detectors are hidden from direct view during critical incidents.

Operational Job

Provides remote visual indication of concealed fire detectors, helps quickly identify alarm location, supports faster inspection and maintenance, reduces access delays, and enables clear alarm recognition in visually obstructed or restricted installation areas.

FAQ

What is a Response Indicator Concealed 503 used for?

The Response Indicator Concealed 503 is used to provide a remote visual alarm indication when a connected fire detector activates. It is ideal for locations where the detector itself is not directly visible. 

It is commonly installed in false ceilings, high-depth ceilings, air-conditioning ducts, outside rooms, laboratories, cabins, stores, and other visually obstructed or restricted areas. 

It conforms to Government of India CPWD DSR specifications, making it suitable for government, commercial, industrial, and institutional projects. 

When a fire detector activates: 

  • The concealed response indicator turns ON immediately 
  • Bright red LEDs provide clear visual confirmation 
  • The alarm source is identified without opening ceiling or ducts

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