Endress Hauser Conductive Point Level Detection Liquipoint FTW33 FTW32 FTW31 E+H Point Level Sensor

What is Liquipoint FTW31

The Liquipoint FTW31 is a conductive pointlevel detector (point level switch) designed for liquids that conduct electricity. It’s used to detect when the liquid reaches a certain level (or multiple levels) in a tank or vessel — for example: overfill protection, dry-run protection of pumps, controlling pump start/stop between two levels, etc.

Unlike continuous level sensors, it detects at specific points (electrodes/rods) rather than giving the whole level profile.

How it Works (Measuring Principle)

• It uses conductive probing electrodes (rods). The liquid must be conductive (minimum conductivity required) so that when the liquid touches the probes, a circuit completes via the liquid, signalling that level is reached.
• The FTW31 can have multiple switching points on a single probe: up to 5 rods/electrodes ‒ meaning you can detect multiple distinct levels with one probe.
• There are no moving parts, which helps reduce wear and maintenance.

Key Specifications

Here are the typical technical data you should know about:

Advantages

Some of the benefits of using FTW31:

• Multipoint detection with one probe: Up to 5 switch points allow you to monitor several levels with one sensor. Saves cost and simplifies installation.
• Simple, robust construction: No moving parts → more reliable, less wear, less maintenance.
• No calibration required for many common conductive liquids; standard settings are provided.
• Wide temperature and pressure range suitable for many industrial processes.
• Good for safety applications like overfill prevention, dry-run protection, etc.

Limitations & Considerations

Things to check / watch out for:

• The liquid must have sufficient conductivity (at least ~ 10 µS/cm). If the liquid is very pure (low ion concentration) and non-conductive, the detector may not work reliably.
• Build-up or deposition on the electrodes (scale, sludge, etc.) can affect performance. If the probes are coated or partially insulated, detection may be delayed or false.
• Multiple rods means multiple exposed points; electrical insulation and mounting must prevent false triggering via unintended paths (e.g. via tank wall, mounting brackets, or condensation).
• In aggressive or corrosive liquids, material compatibility (electrode/stem housing) is important.
• Safety/environmental/explosion certifications must match the application when in hazardous areas. FTW31 offers these, but the specific version and installation must comply.