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Bilgmon 488 Master Unit

Master Unit BilgMon 488

The BilgMon 488 Master Unit is the central control module of the Brannstrom BilgMon 488 system. It is not a complete bilge alarm system on its own – it must be combined with a compatible Sensor Unit (measuring cell). The Master Unit has a durable housing with LCD display, buttons and LEDs. It receives wireless signals from the sealed Sensor Unit, processes the oil content and separator signals, triggers alarms and logs events in its integrated memory. IMO-required data can be retrieved via the LCD display or USB.

Advantages for you:

  • Easy to operate
  • Stocked at Insatech warehouse
  • Cost friendly

We deliver directly and globally to end-users, agents, and resellers.
Contact us at quotes@insatech.com.

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Which BilgMon 488 Master Unit do I need? 
Version and compatibility check

Brannstrom manufactures the BilgMon 488 Master Unit in several versions. To find the correct replacement, check these four points on your installed unit:

  1. Voltage version: 115/230 V AC or 24 V AC/DC

  2. Alarm limit version: standard 15 ppm (programmable 1–15 ppm). Brannstrom also manufactures a special 5 ppm version (programmable 1–5 ppm).

  3. Production series: series 4 (4A, 4AE, 4AC, 4EDA, 4BFA) or series 5 (serial numbers 5xxA, 5xxE, 5xxF)

  4. Sensor Unit colour: black, blue or silver. A Master Unit only works with the matching Sensor Unit.

Sensor Unit and Master Unit compatibility, according to Brannstrom’s technical information “Production versions” (5 December 2024):

Sensor Unit Compatible Master Unit series
Black (series B, 1B, 2B) A, 4A, AE, 4AE, 4AC and series 5 with serial number 5xxA
Blue (series EDB, 1EDB) EDA, 4EDA and series 5 with serial number 5xxE
Silver (series BFB) BFA, 4BFA and series 5 with serial number 5xxF

Wiring: on series 4, the Master Unit terminal numbers are the same as on older installations (series A, AE, EDA, BFA). Series 5 has slightly different terminal numbers, so compare the wiring diagrams before installation. Installation and wiring must follow the applicable manufacturer instructions.

Send us the current Master Unit details and system version, and we will confirm availability and the correct replacement and prepare a quotation. See also BilgMon 488 production versions.

 

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BilgMon 488 Master Unit series 5 - improved features

Series 5 Master Units are produced in parallel with series 4 and add:

  • Flow switch input: an extra signal input for the optional flow sensing switch. A flow alarm is treated like any other alarm: “No Flow” is shown on the display and recorded in the log, without affecting the logging of other operations such as separator activity.
  • Higher current limit on the ASD relay output
  • Sensor Unit age reminder
  • Configurable signal output: current output (0–20 mA or 4–20 mA, corresponding to 0–30 ppm) or digital RS422 data output with oil content and status information

Only series 5 has a dedicated input for the flow switch. See the BilgMon 488 Flow Switch for installation and flow-rate models.

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Insatech employee showing the Brannstrom BilgMon 488

Upgrading from series 4 to series 5

  • Terminals: most terminals keep their function, but the numbering has changed. Compare the wiring diagrams before installation.
  • Sensor Unit: make sure the Sensor Unit colour (black, blue or silver) matches the new Master Unit, see the compatibility table.
  • Flow switch: use the new flow switch input, if applicable.

More information: How to change from version 4 to version 5 and Replacing old Master Units with series 5 units.

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BilgMon 488 Master Unit battery replacement (RTC battery)

The RTC backup battery is connected in parallel with a backup capacitor, so the BilgMon 488 can keep its RTC (real time clock) running for a few hours even without the battery. The RTC battery (CR1225 type) is located on the underside of the Master Unit lid. An RTC failure alarm means the real time clock has stopped. On newer units you can replace the battery yourself.

Procedure for replacing the battery:

  1. Disconnect the power source.

  2. Remove the lid of the Master Unit by loosening the 4 screws at the corners.

  3. Press the metal clip holding the battery and extract the battery from the socket.

  4. Insert a new CR1225 battery promptly, ideally within a few hours.

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BilgMon 488 Master Unit construction

The Master Unit is an enclosure with LCD display, buttons and LEDs. It houses all the electronics used for controlling the bilge alarm and storing data, and it is available for 115/230 V AC or 24 V AC/DC supply.

The main memory, which logs bilge alarm events, is mounted in the lid of the Master Unit. The IMO-required data is stored in the Master Unit housing, so the Sensor Unit can be replaced with the data remaining on board. The data can be retrieved via the LCD display or via USB (separate cable and software). The RTC backup battery is located on the underside of the lid, see battery replacement.

The Master Unit communicates wirelessly with the Sensor Unit. The Sensor Unit is hermetically sealed and should not be opened. It contains the electronics for measuring the sample stream and holds the calibration data, see the Black Sensor Unit and Blue Sensor Unit.

Need the complete unit? See the complete BilgMon 488 system.

Mechanical Installation Bilgmon488 Brannstrom 1024 16X9

Master Unit settings: alarms, autoflush and simulation

Alarm settings: the Master Unit has two alarm outputs. Alarm 1 (valve control) has a delay of 0–10 sec, and alarm 2 (annunciation) has a delay of 0–600 sec, both user adjustable. Alarm points 1 and 2 can be set between 1 and 15 ppm, with an alarm hysteresis of 0.5 ppm below the alarm point.

Autoflush: the Master Unit can be configured to autoflush. This function flushes the sensor tube with clean water at the intervals set in the settings menu. Autoflush only runs when the unit is in the main menu, not during monitoring or analysis.

Simulation: in the simulation menu you can simulate the ppm input from the Sensor Unit and the separator status, to check that the unit is installed correctly and responds to different oil content measurements. Simulated events are recorded in the log, starting with a SIM_ON event and ending with a SIM_OFF event. The unit must be in POWER mode (powered on, separator not running). See the simulation mode in the Version 5 manual.

For cleaning and calibration of the Sensor Unit, see the Sensor Unit pages and the Calibration Check Kit.

The Master Unit in the 15 ppm bilge alarm system

15 ppm bilge alarm monitors the oil content of the separated/filtered water and stops the discharge into the sea if the oil content exceeds 15 ppm (parts per million). It is normally used together with the ship’s oil filtering equipment, also known as a bilge water separator or OWS system. The BilgMon 488 is type approved for this purpose according to IMO MEPC.107(49).

In the BilgMon 488, the Master Unit triggers the alarms and controls the discharge valve when the oil content exceeds the alarm points. For the complete system description and the MARPOL and Port State Control requirements, see the complete BilgMon 488 page.

Rules and Regulations for the 15 ppm Bilge Alarms

According to MARPOL Annex I, ships of 400 gross tonnage and above must be fitted with a bilge water separator, and on ships of 10.000 gross tonnage and above the bilge water separator must additionally be fitted with a 15 ppm bilge alarm.

However, ships between 400 and 10.000 gross tonnage are also required to have the 15ppm alarm in order to be allowed to operate the bilge water separator, when the ship is in one of the following "Special Areas" as defined by MARPOL:

  • The Mediterranean Sea
  • The Black Sea
  • The Baltic Sea and the North West European waters
  • The Red Sea and the Gulf of Aden
  • The Arabian Gulf
  • The Oman area of the Arabian Sea.

For details see Reg.14 & 15 of MARPOL Annex I (Consolidated Edition 2006).

Compliance with IMO MEPC.107(49) Regulations

Ships built before 2005 may operate with equipment meeting the requirements of older IMO Rules, but ships built in 2005 and later must be fitted with bilge separators and 15ppm bilge alarms type approved According to MEPC.107(49).

For details see paragraph 1.3 of MEPC.107(49).

AMSA PSC procedure

AMSA’s (Australian Maritime Safety Authority) Port State Control Officers (PSCOs) inspect oily-water separators, filtering equipment, and alarms per Resolution A.1185(33). Testing ensures that effluent samples flow correctly to the 15ppm bilge alarm and that the automatic stopping device activates when oil content exceeds 15ppm. Failure to meet MEPC.107(49) can result in non-compliance and vessel detention.

Do you want to learn more? Read more here.

Get in Touch with Our Experts

Insatech Medarbejdere Website MSR
For technical questions

Martin Søvind Jensen

Tel: +45 2761 4502

Email: Marine@insatech.com

Write to Martin

Websitebillede Miho Hni Anan Frej (1)
For commercial inquiries

Our team of Sales Specialists

Tel.: +45 5537 2095

Email: quotes@insatech.com

 

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We Deliver Directly to End Customers, Resellers, and Agents – Globally

At Insatech, we are proud to offer our high-quality products to all customers worldwide. Whether you’re an end customer, a reseller, or an agent, you can purchase directly from us.

By choosing us, you gain direct access to all our products, eliminating the need for intermediaries. Our global distribution possibilities ensure fast and reliable delivery to your doorstep, wherever you are.

We strive to make it easy for you as an end consumer to find the products you are looking for while supporting agents and resellers looking to grow their business. Whether you’re buying for your use or resale, we’re here to meet your needs.

Discover how simple it is to work directly with a trusted global distributor – shop with confidence at Insatech today!

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Brannstrom Sweden

 

Why We Offer Brannstrom Products

Insatech offers Brannstrom solutions for their engineering precision, durability, and proven compliance with strict environmental standards. With full in-house design and manufacturing, Brannstrom delivers monitoring systems tailored to specific operational needs - for example the 15ppm bilge alarm type BILGMON 488

These solutions enable reliable performance and regulatory compliance across marine and industrial applications.

 

Bilge Alarm Tailored to Your Application

Brannstrom has a long tradition of developing application-specific systems, engineered in close collaboration with clients and tailored to their exact requirements - drawing on decades of design and development experience.

See all Brannstrom products here

Brannstrom Bm488 Cell
Specifications
Range

0...30 ppm
Resolution

0.1 ppm
Accuracy

According to IMO MEPC.107(49)
Response time

< 3 sec
Alarms
  • Alarm 1 (valve control) delay: 0-10 sec user adjustable
  • Alarm 2 (annunciation) delay: 0-600 sec user adjustable
  • Alarm points 1 and 2: 1-15 ppm user adjustable
  • Alarm hysteresis: 0.5 ppm (below alarm point)
Data storage and retrieval
  • Calibration storage: Stored in sensor housing
  • IMO required data: Stored in BilgMon488 main housing
    (sensor housing may be replaced with data remaining on board)
  • IMO required data retrieval: Via LCD display or USB
Output
  • 0...20 mA
  • 4...20 mA
Communications

USB serial communication (separate cable and software)

Product Specification and manuals

  • Data Sheet - BilgMon488 Bilge Monitor - Brannstrom
    English | pdf
  • Owners Manual - BilgMon488 Bilge Monitor - Brannstrom
    English | pdf
  • Article - BilgMon488 Bilge Monitor - Brannstrom
    English | pdf
  • Article - BilgMon488 Bilge Monitor- replacing old master units - Brannstrom
    English | pdf
  • Data Sheet- BilgMon488 flow switch - Brannstrom
    English | pdf
  • Brochure - BilgMon488 flow switch - Brannstrom
    English | pdf

Instruction manuals: Older versions

  • BilgMon488 Instruction Manual vT
    English | pdf

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