Bosch Automatic Fire Detectors, LSN Improved Series

1 Product Description

The 520 Series Fire Detectors combine the advantages of LSN improved technology with the benefits of flush-mounting and color integration. These detectors can be connected to any LSNi fire alarm control panel or LSN classic fire alarm control panels.

The detectors are available in white and transparent versions with color inlay sheets for seamless integration into various environments. Their design, featuring an easy-to-clean surface and the absence of an optical labyrinth, makes them suitable for dusty environments. The discreet design allows for use in areas where minimal protrusion is desired.

Equipped with two separate optical sensor systems, these detectors are resistant to interference from sources like insects. The analyzed scattered light is projected into the free space below the detector. Dust accumulation is continuously monitored, and the detector adjusts its threshold (drift compensation) accordingly. Severe contamination triggers a fault notification.

The series includes optical fire detectors and multi-criteria detectors with an additional gas sensor (FAP-OC 520). The combination of smoke and gas sensors, analyzed using advanced signal processing methods, provides high resistance to false alarms and broad applicability in environments unsuitable for traditional smoke detectors.

Integrated rotary switches allow for automatic or manual address assignment. The FAP-520 Detectors can be directly connected to the LSN (Local Security Network).

1.1 System Description

All 520 Series detectors feature two optical sensors and a contamination sensor. The FAP-OC 520 multi-sensor detector includes an additional gas sensor.

Detector sensitivity can be programmed via the LSN network using the programming software. All sensor signals are continuously analyzed by the internal signal processing unit.

The combination of optical sensors and the CO sensor in the OC detector allows for use in environments where small amounts of smoke, steam, or dust may be present due to activities. An alarm is triggered only when the signal combination matches the programmed characteristic schema.

1.2 Detector Configuration

The detector's front view shows the sensors:

• 1: Optical sensor
• 2: Receiver (photodiodes)
• 3: Transmitter (LEDs)
• 4: CO sensor (OC variants only)

The two-color LED indicates the operational status and alarm:

• Stand-by: LED is off
• Alarm: LED flashes red
• Fault: LED is off
• Test mode: LED flashes green once every second

1.3 Sensor Technology Description

Optical Sensor (Smoke Detector)

The optical sensor operates on the scattered light principle. LEDs emit light into a defined angle, and smoke particles scatter this light onto photodiodes, which convert the light quantity into an electrical signal. Optical daylight filters and electronic filtering minimize interference from ambient light.

The detector analyzes the temporal progression and correlation of optical sensor signals to distinguish between fire and interference sources like insects or objects. It also identifies errors in the evaluation electronics and LEDs.

Chemical Sensor (CO Gas Sensor)

The gas sensor detects carbon monoxide (CO), hydrogen (H), and nitrogen monoxide (NO). CO oxidation on an electrode generates a measurable current proportional to the gas concentration. The CO sensor is monitored for internal capacity; deviations trigger a fault signal, and the detector operates solely as a smoke detector.

Contamination Sensor

The contamination sensor continuously measures and analyzes the degree of contamination on the detector's surface. Service personnel can read the contamination level in three stages.

1.4 LED Operation

The two-color LED indicates the detector's status. Sensors self-monitor and adjust sensitivity according to the programmed threshold. Significant contamination sends a message to the fire alarm control panel. During an alarm, the LED flashes red. The detector returns to standby after the alarm is reset by the control panel and the cause is removed.

2 Installation/Configuration Guidelines

2.1 General Guidelines

Note: The 520 Series detectors are approved for indoor use only. They must be mounted in the supplied FAA-500 Series sockets, which in turn must be installed in a FAA-500-BB (ceiling mounting) or FAA-500-SB-H (surface mounting) back box.

Installation must comply with country-specific standards and guidelines.

The FAP-OC 520, like the FAP-O 520, must be installed according to guidelines for optical detectors (EN 54 and VDS 2095).

A clear hemispherical space with a radius of 50 cm must be maintained around the detector. Ensure no people, large animals, plants, opening doors, or other objects are within this area, and no part of the detector surface is covered.

Detectors should be installed out of reach. The recommended minimum installation height by Bosch is 2.70 m.

Do not install detectors in areas with high-intensity infrared light (e.g., rooms with IR interpretation systems).

Detectors must not be exposed to direct sunlight. Maintain a minimum distance of 50 cm from lamps. Avoid mounting detectors within a lamp's light beam.

Sockets are equipped with a spring for mounting in concrete and wooden ceilings (blue marking). For installation in suspended ceiling panels, use the softer spring (yellow marking). Note that this application may not comply with EN54-7.

Maximum permissible air velocity: 20 m/s.

2.2 Network Topologies for LSN Improved

In the LSN improved version, detectors can be configured in various topologies: loop, spur, T-branch, or mixed loop/T-branch structures. Mesh structures are not supported.

LSN improved allows for any number of nodes, branches per node, and elements per branch, as long as the total number of elements does not exceed 254. Connections can be placed anywhere on the LSN line.

Detailed information on topologies can be found in the central unit's system manual.

Note: When configuring the installation, consider the expected total current and loop resistance to ensure each detector receives at least 15 VDC. Use the Safety Systems Designer (SSD) for detailed planning.

If an LSN classic device is connected to the loop or spur, only loops or spurs can be used. T-branches cannot be configured.

3 Installation

3.1 Back Box for Ceiling Mounting

Note: The 520 Series detectors must be installed exclusively with an FCA-500 Detector socket, combined with a FAA-500-BB back box for ceiling mounting or a FAA-500-SB-H back box for surface mounting.

Note: Sockets have a spring for mounting in concrete and wooden ceilings (blue marking). For suspended ceiling panels, use the softer spring (yellow marking). This application may compromise shock resistance according to EN 54-7.

The back box for ceiling mounting is made of white polypropylene and features four cable entries with rubber seals suitable for cable diameters up to 1.4 cm. It can accommodate approximately 30 cm of cable length.

Note: The suspended ceiling should not exceed 32 mm in thickness. A minimum clearance of 11 cm is required above the suspended ceiling.

Drill a 130 mm diameter hole (tolerance -1 mm to +5 mm) in the suspended ceiling.

The back box (FAA-500-BB) has mounting points:

• 1: Bracket
• 2: Screws for attaching the socket
• 3: Cable entry

Installation steps:

1. Pull cables through one of the cable entries (3). Use a cable tie to secure the cable jacket.
2. Insert the back box into the suspended ceiling from below.
3. Align the triangular markings (M) on the outer edge of each back box to create a straight line for the detector's center windows for a harmonious appearance.
4. Secure the brackets (1).

Caution: Using power screwdrivers is not recommended for soft suspended ceilings.

3.2 Detector Socket/Detector Socket with Relay

The socket housings are made of white polycarbonate. Screw terminals (for cables with diameters from 0.3 mm² to 3.3 mm²) ensure secure electrical connection. Sockets have three cable tie brackets.

Note: A repeater indicator cannot be connected if relay sockets are used.

Connecting the Socket

Wire the LSN socket according to the markings on the outer ring (3).

Socket Connections:

Wiring Diagram:

The diagram shows the connections for the FAA-500(-R) socket, including LSN connections (a1/a2, b1/b2), power (+V, OV), and connections for the repeater indicator (C) and shielding.

* Connections for looping power to other LSN elements.

** Refer to Detector Sockets, page 30 for switching capacity.

The socket is secured to the back box with four screws. It can be rotated up to 20° in the elongated slots for precise alignment.

3.3 Address Assignment

The detector's address is set using the three rotary switches on the back of the detector.

Set each switch using a flat-head screwdriver. The switches click when turned. All delivered detectors are factory set to 000.

Rotary Switches:

• CL: LSN classic mode
• Xxx: Hundreds
• xXx: Tens
• XXX: Units

When connecting to BZ 500 LSN, UEZ 2000 LSN, or UGM 2020 fire alarm control panels, all detectors must be addressed with CL 0 0.

When connecting to a modular fire alarm control panel, addresses can be assigned automatically or manually. For manual assignment, all detectors on the same loop, spur, or T-branch must have an address between 001 and 254. Addresses between 255 and 299 are not permitted and will cause a fault notification.

If the control panel assigns addresses automatically, all detectors must have the address 000.

3.4 Detector and Bezel

Note: The packaging for detectors with a C-sensor is made of tear-resistant PE-ALU laminated foil and should be opened carefully. Remove the protective foil only when the detector is to be installed.

3.5 Flush-Mount Box for Concrete Ceilings

The FAA-500-CB flush-mount box is used for installing detectors in concrete ceilings, facilitating pipe connections. It is placed, secured, and fixed to the concrete form to prevent movement. Ensure nails are fully within the polystyrene area to avoid interference when cutting the polystyrene.

Pipe or cable entries can be made in the walls using a universal cutting tool. After removing the formwork, the front part (1) is opened with a jigsaw or hole saw. Subsequently, a FAA-500-BB back box for ceiling mounting is placed in the opening for the socket and detector.

3.6 Back Box for Surface Mounting

The FAA-500-SB-H back box is suitable for surface and flush-mount cable channels. The box has a seal for damp rooms. For surface-mount cable channels, use the knock-out holes on the side. The bottom has two openings for flush-mount cable channels. With 13.5 mm cable glands, the maximum cable thickness is 12 mm.

Mounting occurs:

• via the elongated slots or
• via the four mounting holes for direct mounting onto 4-inch electrical boxes or single switch boxes (for VS).

The socket is mounted in the back box at four mounting points.

3.7 Repeater Indicator

A repeater indicator is required when the detector is not directly visible, or when installed in double ceilings or floors.

Repeater indicators should always be installed in corridors or access paths leading to the relevant sections or rooms of the building.

Note: With non-shielded cables for connecting the repeater indicator, the maximum cable length is 3 m. There is no restriction when using shielded cables.

Installation of the FAA-420-RI Repeater Indicator

Warning! Faults and Damage: If the maximum current consumption of the connected detector exceeds 20 mA, it can lead to faults or damage to the repeater indicator. Ensure that the maximum current consumption of 20 mA is not exceeded. Use Bosch automatic point detectors with an internal resistance to limit current consumption.

Remove the cover of the base plate before mounting:

1. Release the mounting hook by pressing it with a flat object and carefully lift the cover.
2. Remove the connection print board for easy access.
3. Mount the base plate with two or four screws onto a dry and even surface.

For surface cables, break out the pre-stamped cable entries.

For flush wiring, insert the cables through the opening below the connection print board.

Secure the cable with a cable tie to the base plate.

Warning! Faults and Damage: Observe both the maximum permissible current supply and the input voltage range for the operating modes. Connect the repeater indicator as shown.

Mode and Connection Terminal:

Use only in modes 1 and 3 when connecting to LSN detectors.

For FAA-420-RI-ROW:

1. Align the cover with the socket so that the two hooks engage in the slots.
2. Lightly press the cover onto the socket until the mounting hook clicks into place.

For FAA-420-RI-DIN:

1. Connect the repeater indicator as shown.
2. Align the cover with the base plate so that the two hooks engage in the slots.
3. Lightly press the cover onto the base plate until the mounting hook clicks into place.

4 Programming

LSN detectors are programmed according to the required operating mode. Programming is done using the programming software on a PC or laptop connected to the fire alarm control panel.

The appropriate sensitivity of the multi-sensor detector is programmed by specifying the operating location (e.g., computer room, office, large kitchen). The choice of operating location determines the optimal characteristic schema for evaluating fire and fault variables.

If a low sensitivity is set for the optical sensor according to the operating location, the alarm will only trigger if the detector simultaneously registers high levels of smoke and CO. This occurs with open or smoldering fires.

Programming the multi-sensor detector and linking all detectors through algorithms significantly increases the reliability of smoke detection and reduces the number of false alarms.

Operating Locations for Multi-Sensor Detectors (FAP-OC 520)

Sensitivity settings (O-unit and C-unit) are adjustable via the programming software.

The sensitivity of the optical sensor in the FAP-O 520 can be set at three levels. Depending on the operating location, the optical sensor is adapted to the environmental requirements. For fire detection, the temporal behavior of the characteristics of fire is also evaluated, which differs significantly from the temporal behavior of fault variables.

Recommended Settings for Optical Detectors (FAP-O 520)

Note: To perform functional tests for the FAP-O 520 and FAP-OC 520 detectors, they must be in test mode. This can be activated via the fire alarm control panel or the reed switch on the detector using a magnet (see Maintenance and Service, page 23).

5 Maintenance and Service

Note: The 520 Series detectors do not need to be removed from their sockets for routine maintenance. If a detector needs replacement due to design changes or damage, it must be performed by authorized personnel. The system must be offline during replacement, and alternative emergency evacuation measures must be in place.

In Germany, maintenance and inspection of safety systems must comply with DIN VDE 0833. These regulations specify maintenance intervals as determined by the manufacturer.

Maintenance and inspection should be performed regularly by trained technicians. Bosch recommends a functional and visual inspection at least once a year.

Remote maintenance is permitted for certain procedures, including detector activation with a test criterion. FAP-520 series detectors comply with remote maintenance requirements. Remote operational tests are only permitted if they are conducted in accordance with the manufacturer's approved test procedure.

Test Steps

FAP-OC 520

Note: Due to the expected lifespan of the gas sensor, the FAP-OC 520 detector will deactivate its C-sensors after approximately 5 years. The detector will then function only as an O-detector. The fire alarm control panel will display a corresponding fault message. Replace the detector immediately to continue benefiting from the higher reliability of the OC detector.

Note: The cleaning frequency depends on environmental influences. The detector can be cleaned with a soft cloth and plastic cleaner. Cleaning should only be performed in test mode.

5.1 Service Guidelines

Note: The serial number, contamination level, operating hours, and current analog values of all configured detectors can be read from the fire alarm control panel's display.

Contamination Level

The contamination level is given as a percentage:

Operating Hours

Displays operating hours since commissioning.

Current Measured Values

Analog value of the scattered light sensor:

CO Value: Current measured value of the CO sensor (FAP-OC 520 only). The maximum measured value is 1023.

5.2 General Guidelines for Detector Testing

The FAP-OC 520 detector has an additional sensor for detecting CO in case of fire. For critical environmental requirements, the CO sensor offers improved response behavior and additional stability against unwanted alarms. For fire detection, FAP-520 detectors evaluate the temporal behavior of fire characteristics, which differs from the temporal behavior of fault variables. Therefore, the detector must be in test mode during an operational test. Switching to test mode can be done in two ways, described in the alternative test procedures (see below).

Note: Detectors programmed for two-detector dependency must be tested according to the first alternative (in test mode).

For detector testing, you will need:

• Detector test device for optical fire detectors
• FAA-500-TTL test adapter with magnet
• For the OC detector, a CO test gas is also required for the detector with the CO sensor.

5.3 Inspection Procedure for FAP-OC 520

5.3.1 Option 1

Use the remote test function to test the detectors.

Note: Remote tests are only permitted if they are conducted in accordance with the manufacturer's approved test procedure.

5.3.2 Option 2

1. Set the detector zone to be inspected to test mode on the control panel. This automatically places the detector in service mode and prepares it for the detector test. Only in service mode can the individual sensors of the detector be activated with the corresponding test device. For an alarm, all sensors must be activated simultaneously. The C-sensor is activated with the CO test spray, and the O-sensors by covering them. O-test gas is not required.
2. Hold the test device under the detector so that the test cup is flush with the bezel and seals tightly.
3. Ensure the test cup does not tilt, as this could lift the detector and dislodge it from its mounting.
4. Spray with the CO test gas for approximately 1 second.
5. The test cup must remain over the detector until the detector is activated. It may take up to 20 seconds for the CO test gas to distribute in the test cup and for the sensor to activate.
6. Both scattered light areas are covered by the test cup, activating both optical sensors simultaneously.
7. The detector activates the alarm, and the red alarm LED flashes.

5.3.3 Option 3

The detector can be tested during normal operation using a test device with a magnet.

Note: Ensure that the alarm is not transmitted to higher-level systems. Programmed activations of the control unit are saved and executed.

The image shows the position of the reed switch (pos. R) on OC detectors. If you imagine a line through the detector's LED as the 12 o'clock position, the reed switch (pos. R) is located approximately at the 2 o'clock position.

Test Procedure:

1. Place the magnet near the reed switch.
2. Once the reed switch is activated, the detector's green LED flashes once per second. The detector will remain in test mode for 60 seconds with automatically set test parameters (e.g., reduced delay to 15 seconds). The green LED flashes as long as the detector remains ready for the test.
3. Hold the test device under the detector so that the test cup is flush with the bezel and seals tightly. Ensure the test cup does not tilt, as this could lift the detector and dislodge it from its mounting.
4. Proceed as in the first alternative: spray with CO gas, place the test device on the detector for approximately 20 seconds until the alarm is activated.

Note: Longer activation times may occur in case of programmed temporary alarm storage.

Both scattered light areas are covered by the test cup, activating both optical sensors simultaneously (O-test gas is not required). The detector activates the alarm, and the red alarm LED flashes.

5.4 Inspection Procedure for FAP-O 520

5.4.1 Option 1

Use the remote test function to test the detectors.

Note: Remote tests are only permitted if they are conducted in accordance with the manufacturer's approved test procedure.

5.4.2 Option 2

1. Set the detector zone to be inspected to test mode on the fire alarm panel. This automatically places the detector in service mode and prepares it for the detector test.
2. Hold an object large enough (e.g., the detector test device or a detector replacement) in both scattered light areas until an alarm is activated. O-test gas is not required.

5.4.3 Option 3

The detector can be tested during normal operation using a test device with a magnet.

Note: Ensure that the alarm is not transmitted to higher-level systems. Programmed activations of the control unit are saved and executed.

The image shows the position of the reed switch (pos. R) on O detectors. If you imagine a line through the detector's LED as the 12 o'clock position, the reed switch (pos. R) is located approximately at the 2 o'clock position.

1. Once the reed switch is activated, the detector's green LED flashes once per second. The detector will remain ready for the test for 60 seconds with automatically set test parameters (e.g., reduced delay to 15 seconds). The green LED flashes as long as the detector remains ready for the test.
2. Hold the test device under the detector so that the test cup is flush with the bezel. Covering the scattered light areas simultaneously activates both optical sensors (O-test gas is not required).
3. The detector activates the alarm, and the red alarm LED flashes.

Note: Longer activation times may occur in case of programmed temporary alarm storage.

5.5 Repair

In case of defects, the entire module/device will be replaced.

5.6 Disposal

Defective electrical and electronic equipment/modules must not be disposed of as household waste. They must be disposed of in accordance with applicable standards and guidelines (e.g., WEEE in Europe).

Packaging film for the fire detector with C-sensor: The packaging bag for multi-sensor detectors with a C-sensor is made of tear-resistant PE-ALU laminated foil and can be disposed of with household waste.

6 Technical Specifications

6.1 Detector and Bezel

Electrical

Design

Flush-Mounting in Ceiling with FAA-500-BB

Note: A clearance of at least 110 mm is required above the suspended ceiling.

Environmental Requirements

Mechanical Specifications

6.2 Detector Sockets

6.3 Mounting Boxes

FAA-500-BB Back Box for Ceiling Mounting

Installation Dimensions:

• Thickness of Suspended Ceiling: max. 32 mm
• Required Drill Hole: Ø 130 mm (tolerance -1 mm to +5 mm)
• Mounting Height: 11 cm
• Max. Cable Diameter: 1.4 cm

FAA-500-CB Flush-Mount Box for Concrete Ceilings

FAA-500-SB-H Back Box with Seal for Damp Rooms

6.4 Repeater Indicator

Technical Specifications

7 Appendix

7.1 Abbreviations

7.2 Order Overview

7.2.1 Detector and Bezel

Color Inlays for FAP-O 520-P, FAP-OC 520-P, and FAA-500-TR-P:

7.2.2 Detector Sockets/Repeater Indicators

7.2.3 Mounting Boxes

7.2.4 Service Tools/Accessories

* LE = unit of delivery, ST = piece, PAK = packaging