ROM3 On Board Monitor


Liquip offers an extremely small and lightweight on board overfill protection monitor or an integrated overfill and retained product protection monitor.

Liquip’s ROM III series of monitors provide real world safeguarding against costly overfills every day. These monitors are designed and manufactured to deliver years of high performance, even under extreme conditions.

These monitors can be used to provide fuel overfill monitoring in a single compartment road tanker/storage tank or to provide a dedicated earth assurance device for use at a terminal.

The ROM III monitor detects and communicates a pending overfill condition to a loading rack control monitor, and signals which tank compartment is overfilled.

The ROM III monitor (3308R-LIQ) can also detect and communicate a retain condition to a loading rack control monitor. This control system will enable a tank truck/trailer to load at API optic, thermistor or float petroleum loading rack monitors while using only two wire optic sensors. If all of the optic sensors do not detect any liquids, the monitor provides the necessary signal information to the appropriate API sockets to enable loading of the tank trailer truck.

The ROM III Onboard Monitor has been designed for use with any Liquip 2-Wire Overfill Sensors.


Features & Benefits

• Extremely small, lightweight.
• Support for tanks with up to 8 compartments using 2-wire overfill and retain sensors.
• Detects and communicates the sensor status and overall unit’s “permissive to load” (the tanker) status to a loading rack monitor via its socket outputs.
• 2 relay contacts one I.S. and one NON I.S.
• Diagnostic capabilities with optic rack monitors.
• Low power indication.
• Relay outputs can connect directly to a pump, control valve, alarm etc.
• Can replace Liquip’s MPP102 mini monitor. Contact Liquip for change out procedure. (Doc No. P 59132).
• For a full list of features please contact Liquip for a copy of the ROM III IOM (Doc No. H53265PAL).


Recommended products for replacement

    Technical Information

    Safety Approvals 
    FM, ATEX and IECEx (zone 2).

    Input Voltage range 
    9V to 30 VDC.

    Input Voltage Fuse
    Max. 0.5A, slow blow, located in safe zone.

    Ambient Operating Temperature
     -40ºC to +70ºC.

    Max Surface Temperature

    Non I.S. Relay (TB1) Voltage
     30 V.

    Non I.S. Relay (TB1) Relay Current
     5 A.

    I.S. AUX Out (TB4) Voltage
     20 V.

    I.S. AUX Out (TB4) Current
     50 mA.

    Aluminium housing enclosure with a windowed cover.

    4 x 7/16" mounting holes using 4 x 8mm bolts.

    Ingress Protection
    IP54 rated.

    2kg (TBC).

    Ordering Information

    LIQ3308-LIQZ: Kit comprises of ROM III OBM + 1910A terminator. 

    LIQ3308-LIQ: ROM III OBM replacement (or when no dummy probe is required).


    Associated Equipment

    Probes: LDP202 Aluminium and Stainless Steel Series. 

    EAC201: Earth Assurance Clamp.

    JB100: Junction Box.

    LIQ1910A: ROM terminator probe

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    3308-LIQ ROM III OBM
    3308-LIQZ Kit comprises of ROM III OBM + 1910A terminator

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