Brannstrom BilgMon 488 Black Sensor Unit (Measuring Cell)

Which BilgMon 488 Sensor Unit do I need? Compatibility check

Brannstrom manufactures the BilgMon 488 Sensor Unit in black, blue and silver versions. A Sensor Unit only works with the matching Master Unit, so check the series and serial number of your installed Master Unit before ordering.

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

The Sensor Unit is replaced without changes to the Master Unit. It communicates wirelessly with the Master Unit, and the Sensor Unit housing is hermetically sealed and must not be opened.

Send us the series and serial number of your installed Master Unit, the colour of your Sensor Unit and, if available, the part or serial number of the Sensor Unit. We will confirm the correct replacement and the most cost-effective solution for your installation and prepare a quotation. See the Master Unit version and compatibility check and the technical article BilgMon 488 production versions.

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Replacing the BilgMon 488 measuring cell

The maintenance schedule for the BilgMon 488 must address two items: the Sensor Unit’s calibration certificate, which expires after 5 years, and a regular calibration check.

When the calibration certificate expires: the certificate is valid for five years. When it expires, the Sensor Unit must be replaced. The crew can easily do this onboard within five minutes, and it does not require any modifications of the Master Unit. All new sensor units are accompanied by a new calibration certificate. The IMO-required data is stored in the Master Unit housing, so it remains onboard when the Sensor Unit is replaced.

When a calibration check fails: the calibration check can be performed at shorter intervals than the validity period of the certificate, using the Calibration Check Kit. If the check fails, thoroughly clean the sensor and go through the installation to check that no air bubbles or particles are measured. If the fault remains, there is a high chance that the measuring cell must be replaced.

Always include a check of the expiry date of the factory-issued calibration certificate in your maintenance of the BilgMon 488. See the Calibration Check Kit page for how to perform the calibration check.

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BilgMon 488 Sensor Unit construction

The Sensor Unit is an enclosure with pipe fittings. It contains the electronics for measuring the sample stream and holds the measurement calibration data. It communicates wirelessly with the Master Unit, so the Sensor Unit is hermetically sealed and should not be opened.

The Master Unit houses all electronics for controlling the bilge alarm and storing data, and it logs bilge alarm events in the main memory in its lid. For the RTC backup battery in the Master Unit, contact us for battery replacement.

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

The Sensor Unit in the 15 ppm bilge alarm system

The Sensor Unit is part of the BilgMon 488, a 15 ppm bilge alarm type approved according to IMO MEPC.107(49). The alarm monitors the oil content of the separated/filtered water and stops the discharge into the sea if the oil content exceeds 15 ppm. The Sensor Unit measures the oil content in the sample stream (range 0–30 ppm), and the Master Unit processes the signal and triggers the alarms. For the complete system description and the MARPOL and Port State Control requirements, see the complete BilgMon 488 page.

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