Three and Four zone fuel oil Leak alarm with audible warning, Large Alpha numeric Display, Alarm Mute and display back light On, push buttons and alarm relay for onward signalling.

The sensors on this system are not suitable for outside use.

The ODS4-3 has been designed to monitor four independent zones for fuel oil leaks including but not limited too, Diesel, Heating and Hydraulic oils via optical sensors.

With no oil leaks being detected, the screen will display “The System is Clear No Alarms to Display”. When one of the detection sensor comes into contact with oil, the audible warning device will sound, the common alarm relay will close and the display will change to advise the sensor zone i.e. “OIL LEAK DETECTED AT ZONE 1”. A mute “Mute Alarm” button is provided to cancel the audible warning. The system will remain in this state until the Oil has been removed from the sensor. If more than one zones detects an oil leak at the same time, the display will latch on to the lowest numbered zone. Once muted, the display will latch onto the next zone in alarm and start the audible warning devise again requiring the “Mute Alarm” button to be pressed again. When the system is clear from alarms, the screen back light will turn off. Once the unit detects an oil leak the back light it will automatically turn on and remain on until the leak has been cleared. A “Screen Light” push button has been provided to allow the back light to be turned on when the system has no alarms to report and will automatically turn off again after five minutes.

The sensors mode of operation is the principle of total internal reflection. An LED and phototransistor are housed in a plastic (Polysulfone) dome. When no liquid is present, light from the LED is internally reflected from the dome to the photo-transistor. When a liquid covers the dome, the effective refractive index at the dome-oil boundary changes allowing some light from the LED to escape. Thus the amount of light received by the photo-transistor is reduced indicating the presents of a liquid.


  • The unit can be supplied as a 3 or 4 zone system
  • A maximum of two sensors can be fitted to each zone
  • Large back lit alpha numeric display
  • Internal Zone Alarm lamps
  • With the exception of mains power, all terminals are of the plug and socket type
  • On board audible warning device to alert local operators of a problem
  • Alarms latched until Mute operated
  • Common alarm relay contact for onward signalling to a BMS
  • Mains power fault relay contact for onward signalling to a BMS
  • Optional individual zone alarm relay contacts for onward signal to a BMS
  • Optional alarm output to a flashing Beacon
  • Optional alarm output to a flashing Beacon and Mutable Sounder
  • Optional SMS text messaging to two phone numbers
  • Optional battery backup

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Beacon for remote indication of an alarm
This 12VDC Flashing beacon can be used to advise of an alarm were noise is an issue such as hospital corridors or noisy environments.


SMS Text Messaging alert unit
For unmanned areas or to advise maintenance staff of a problem. With the addition of our SMS Text Messaging alert unit, an alarm will also be sent in text form to one or two phones. This unit is usually added where the alarm unit is mounted remote from maintenance staff, or in unmanned areas.

SMS Text Messaging alert unit

Battery backup
With the addition of battery backup power the alarm system will operate up to 10 hours when the alarm units mains power is turned off or in a power cut. This is recommended for sensitive areas were a UPS and backup generator power is not available.

Battery backup

AS2 Remote Repeat Alarm
This unit can be fitted to remote areas such as reception areas maintenance rooms or corridors were visual and audible warnings are required.

AS2 Remote Repeat Alarm

Individual alarm relays for each zone
Individual zone alarm relays can be provided to give a volt free normally open, closed in alarm contact that operates when the zone goes into alarm. The contacts can be used to onward signal to Building Management Systems or to control individual water valves.

Individual alarm relays for each zone

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