The Novus WL420 is a high-stability, submersible hydrostatic level transmitter engineered for continuous monitoring in shallow water applications. Operating on the principle of hydrostatic head pressure, the sensor sits directly at the bottom of the container, measuring the weight of the liquid column above it and actively compensating for atmospheric pressure via the vent tube. This provides a more accurate level reading than unvented sensors. These sensors cover process depths from 1 to 2.5 meters, offering an incredibly reliable, low-maintenance alternative to ultrasonic or radar sensors which struggle with sensor dead zones that can cover the top 100mm of tanks.
Piezoresistive Diaphragm Technology: Built with a highly stable 316L stainless steel diaphragm sensor, fully compatible with raw water, chlorinated water, and most semi-aggressive industrial fluids or process oils.
Atmospheric Venting System: The durable Polyurethane (PUR) suspension cable contains an integrated internal atmospheric ventilation tube. This allows the internal sensor cavity to automatically compensate for shifting barometric weather pressures, ensuring your level readouts remain accurate and unaffected by localized weather changes.
Industry-Standard 2-Wire Loop: Features a standard 4-20 mA current output powered entirely by the signal loop (12 to 36 vDC). This allows easy, direct integration into standard PLCs, RTUs, data loggers, and local panel displays.
Rugged Submersible Build: Rated at IP68 for permanent submersion, with a main housing body constructed from 304 stainless steel. The probe body measures 105 mm in length and has a 26.5 mm diameter.
Electrical Safeguards: Features robust internal protection loops, including reverse-polarity protection and an integrated current limiter to safeguard your control instrumentation from installation wiring errors.
Red Wire: Power Supply VCC (+12 to 36 vDC)
Blue Wire: Output Current Signal (4-20 mA Loop Return)
Internal Red Tube: Atmospheric Vent Tube (Must remain completely unobstructed and dry inside your terminal junction box)
Novus also offers the premium, slimline WL320 for specialised deployments, the WL420 remains the undisputed industry workhorse and the most logical choice for standard 1m to 2.5m tank configurations.
By utilising a wider 26.5 mm footprint, the WL420 houses a larger, robust internal sensor element that delivers exceptional long-term stability and high repeatability without the premium price tag of a miniature borehole probe. It strikes the perfect balance for industrial utility tanks: you get the exact same 316L stainless steel measuring diaphragm as the higher-end models, wrapped in a rugged 304 housing that is fully optimised for standard water, oils, and neutral chemical solutions.
At the bottom of the product list are options for protecting the vent tube from water ingress and still leaving the sensor able to actively compensate for the current atmospheric pressure.
Applications
Frequently Asked Questions
The sensors listed below all come with 5m of vented cable. Click the more info and you can opt for a version with 15m of vented cable.
WL420 Submersible Hydrostatic Level Transmitter. Depth Range 1mH2O. 2-Wire Loop Powered 4-20mA Output with a 12-36vDC Power Supply. 5m Polyurethane (PUR) Cable with Ventilation Tube. Over-Pressure 300% FS, Burst Pressure 600% FS. Stainless Steel Sensor with 105mm Body Length and 26.5mm Diameter.
WL420 Submersible Hydrostatic Level Transmitter. Depth Range 1.6mH2O. 2-Wire Loop Powered 4-20mA Output with a 12-36vDC Power Supply. 5m Polyurethane (PUR) Cable with Ventilation Tube. Over-Pressure 300% FS, Burst Pressure 600% FS. Stainless Steel Sensor with 105mm Body Length and 26.5mm Diameter.
WL420 Submersible Hydrostatic Level Transmitter. Depth Range 2.5mH2O. 2-Wire Loop Powered 4-20mA Output with a 12-36vDC Power Supply. 5m Polyurethane (PUR) Cable with Ventilation Tube. Over-Pressure 300% FS, Burst Pressure 600% FS. Stainless Steel Sensor with 105mm Body Length and 26.5mm Diameter.
Accurate hydrostatic measurement relies entirely on balancing the sensor against local atmospheric pressure changes via an internal cable vent tube. To prevent moisture, humidity, and dirt from entering this delicate tube and damaging your transmitter, we highly recommend installing a specialised Vented Compensation Box. This enclosure allows the sensor to breathe freely while utilising a replaceable desiccant to seal out the elements, ensuring long-term system accuracy and preventing premature sensor failure.
Small ABS Compensation Box. Provides a venting point for a depth sensor close to the monitoring location, whilst offering a connection for a longer cable back to monitoring equipment. Enclosure is IP67 rated to prevent water ingress but not air tight.
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