Brannstrom BilgMon 488 Bilge Alarm

Brannstrom BilgMon 488 Bilge Alarm

Separator Spares & Equipment, LLC is trained in the installation, verification, operation, faultfinding, commissioning, and maintenance of the Brannstrom BilgMon 488 Bilge Alarms. 

Separator Spares & Equipment supplies oily water treatment systems, manufactured by Boss Oily Water Separators, which include the Boss 2.2T/107, Boss 5T/107, Boss 11T/107,  Boss 25T/107, Boss 45T/107, and miniBOSS systems.  These oily water separators utilize the Brannstrom BilgMon 488 bilge alarm monitor. 

Brannstrom BilgMon 488 Bilge Alarm Monitor

The BilgMon488 bilge alarm has been designed specifically for use in conjunction with 15 ppm oil-water separators units. The 15ppm bilge alarm type BILGMON 488 is type approved to meet the requirements of IMO Resolution MEPC.107(49), and with its small dimensions, it is ideal also for retrofit on existing separators. The smart detachable measuring cell with wireless communication is easy to remove and replace with a newly calibrated cell if this is preferred to having the system accuracy checked on board.

On special request, the BilgMon488 is also available as a 5 ppm version meeting the requirements of Class notation “Clean Design”.

The BilgMon488 is equipped with two adjustable alarms that are triggered when the oil content of the processed sample exceeds the set limit (1–15 ppm, works-adjusted to 15ppm). Alarm outputs consist of relays and indicator LEDs. Additionally, a 0(4)–20 mA current output signal (corresponding to 0– 30 ppm) is available to enable remote surveillance and recording of oil contents.

The BilgMon488 consists of two main parts, the master unit (housing with LCD, buttons, and LEDs) and the sensor unit (housing with pipe fittings). The master unit contains all the electronics used for control and data storage of the bilge alarm. Mounted in the lid of the master housing is the main memory containing the bilge alarm log. The sensor unit contains electronics for measuring the sample stream. The sensor unit also holds the measurement calibration data. Communication with the master unit is done wireless hence the sensor unit is hermetically sealed and shall not be opened.

The optical sensors monitor the amount of light scattered and absorbed by the oil droplets in the sample stream. Sensor signals are processed by a microprocessor to produce a corresponding oil content (ppm) output. The output is communicated to the master unit where it is processed. The master unit takes action, such as alarm activation, logging, etc., depending on the oil content and the separator signal. Zero-point calibration can be re-adjusted on-site whereas full sensor calibration according to IMO requirements is performed by the manufacturer.

Separator Spares & Equipment provides calibration services, spare parts, new, and/or replacement Brannstrom BilgMon 488 bilge alarms.

Models and Specifications

* Type approved to meet the requirements of IMO Resolution MEPC.107(49).

BilgMon 488 LCD displays "RTC check: FAILED!"

The possible reason for this error code is the real-time clock (RTC) has stopped. You will need to order a replacement part.


  • The lid of the master unit contains a small battery. This batter enables the BilgMon488 to keep track of time and date (real-time clock, RTC).  DO NOT under any circumstance remove the battery as it will cause an unrecoverable error (“RTC check: FAILED!!).
  • DO NOT open the sensor unit as this will invalidate the calibration.

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