Water tank gauges and sensors – monitor the tank fill level
In the water tank gauges and sensors product group, you will find Wema brand gauges and sensors for monitoring the filling level of a water tank: a black gauge suitable for S3/S5 sensors, a 6-screw stainless steel sensor flange, and a water and fuel sensor S3 model in several lengths (150mm, 225mm, 250mm and 275mm) - the correct sensor length is selected according to the depth of the tank so that the sensor float can move throughout the entire tank filling area.
The Wema sensor works on the resistive principle (0–180 ohm) and is compatible with most marine gauges, making it a widely used standard in water and fuel systems on boats. The same sensor model is suitable for both water and fuel tanks, so when choosing, it is important to only ensure the sensor length and the number of flange screws according to your tank - a sensor of the wrong length will give an incorrect reading because the float does not hit the correct filling area of ??the tank.
Always install the sensor at the highest possible point in the tank, vertically, so that the measurement covers the entire tank volume from top to bottom. Check the condition of the flange gasket during installation to avoid leaks, especially if the sensor is installed in an existing tank that has already been used.
The Wema sensor is typically mounted vertically at the top of the tank so that the float arm measures the entire depth of the tank – choosing the right length is important, as a sensor that is too short will not detect when the tank is only partially full, and a sensor that is too long can hit the bottom of the tank and be damaged. The gauge itself usually shows the fill level in four or five steps (from empty to full), which is sufficient for most boating needs without a more precise percentage reading.
The same sensor model will work in both water and fuel tanks, but never confuse the intended use during installation – a fuel tank sensor requires a spark-proof design and proper sealing materials with the fuel, while a water tank sensor does not require the same protection. Always check the compatibility of the sensor and the meter (0-180 ohm standard) before installation.
It is advisable to choose a location on the dashboard where the gauge can be easily seen from the steering position without having to reach out – this is especially important on longer trips where fuel or water levels need to be monitored regularly. The wide popularity of Wema products in the boating industry also means that spare parts and compatible additional sensors are widely available even years after installation.
Wema products are also compatible with many third-party marine instrument panels, making it easy to expand or upgrade the system later without having to replace the entire instrument panel.