Thanks to its impact-resistant housing with high-quality plastic cover and die-cast aluminum base, the 1-pole mechanical surface-mounted thermostat is very robust and can also be used under harsh conditions. The measuring system used works according to the liquid expansion principle and can be used without problems up to a maximum permissible sensor temperature of 230 °C. The immersion tube made of high-quality stainless steel (material no. 1.4571) has a diameter of 8 mm. It is attached using a G 1/2 Form A thread in accordance with DIN 3852/2. The maximum permissible ambient temperature on the housing (protection class IP54) is 80 °C. With the help of a screwdriver, the desired switch-off temperature can be easily set on a scale on the inside after removing the housing cover. If the temperature at the temperature sensor exceeds the set limit, the circuit is opened and the microswitch is mechanically locked. Once the temperature falls below the danger temperature by approx. 10% of the scale range, the microswitch can be unlocked manually. The safety temperature limiter is characterized by a high switching point accuracy of +0/-5% in the upper third of the scale. If the measuring system is destroyed, the circuit is permanently opened and unlocking is then no longer possible. The switching contact is then in a neutral position so that no contacts are switched. If the sensor cools down to a temperature below approx. -20 °C, the circuit is also opened; only when the temperature rises above approx. -20 °C can the STB be unlocked again manually using the restart button. A decisive advantage is that no additional auxiliary power is required for temperature measurement. The electrical connection is made via screw terminals directly on the built-in microswitch, which can directly switch a maximum permissible switching capacity of AC 230 Volt / 10 A. The safety temperature limiter is very flexible
