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Thermal Limit Switch

LS 300

Thermal limit thermal switch with ATEX approval.

Knows if the limit has been reached
With our limit switch, the overfilling of tanks and process containers is prevented. It consists of a sensor (LS300) installed inside the tank and a transducer (LS500) with an output relays. For water-polluting liquids, this overfill prevention device is an indispensable component for environmental protection.
Field of application | LS 300 Thermal Level Switch

Installed and tested in the following applications:

Full and empty notifications in process containers, storage tanks, above-ground tanks, IBCs, tank wagons, vats, bottles and retention ponds.


There is no abrasion since there are no moving parts. A long life time is guaranteed with consistent reliability.

Always fits:

there is almost no installation conditions for which we have not developed a sensor. Whether adaptable, bent or flexible, as an intermediate flange, only 3 mm in diameter or with DN 200 flange; we have a solution.


Various fields of applications: Applications examples Info


The overfill prevention device fulfils the requirements of the German Water Resources Act (WHG).

Easy to get started

Easy installation with a 2-wire terminal to the transducer, fitted independent of polarity. The sensor requires no maintenance after the installation, therefore there are also hidden costs!

Information Sheet

Level Switch LS 300 / 500

FAFNIR LS 300 / LS 500 in brief

InfoReliability proven over 45 years
InfoPolarity-independent two-wire terminal to the transducer
InfoPermanent self-testing
of the sensors
InfoSpace-saving, robust and
corrosion-free design
InfoNo moving parts
InfoNo on-site calibration required
InfoAbsolutely maintenance-free
InfoApproved for Ex zone 0
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