Frost protection thermostats are used on the air part of air-conditioning systems, heat exchangers, heating registers, and similar units to protect them against frost damage and freezing. With the frostTHERM-ATE frost protection thermostats, JUMO is expanding its electromechanical range to include an electronic solution. A special startup function, the integrated case head heater, and the particularly simple operation set this new product apart from the rest.
With the frostTHERM-ATE, the lowest temperature on the probe line is determined over a length of 250 millimeters using a steam-filled probe line and a membrane. The mechanical movement that results is transformed into an electrical signal, is electronically amplified, and can be recorded as a measurement signal DC 0 to 10 V on the analog output. As a result, continuously opening the heating valves or closing the flapper valves is possible. The relay contact that is also available allows the user to directly switch loads up to AC 250 V 6(2) A. This means that fans can be switched off. In addition, the temperature being measured can be recorded as an output signal for further processing (e.g. through an external temperature display).
Per default the frostTHERM-ATE is fitted with a case head heater. This keeps the head temperature between -15 and +15 °C, thereby ensuring that the device functions even in low temperatures. The frostTHERM-ATE has a startup function to prevent the device from switching on and off multiple times while the device starts up. This ensures that the heating valve is completely opened via the 0 to 10 V output before the relay contact switches and puts the whole device out of commission.
After having loosened a small sealing screw all settings on the thermostat can be carried out externally using two push-buttons. Isolating the voltage supply is unnecessary. The switching point and the operating mode can be selected on the frostTHERM-ATE. The switching point can be set to between 1 and 10 °C. In the operating mode the user can choose between operation without a reactivation lock and operation with a reactivation lock. If the operating mode with reactivation lock is selected, the thermostat is locked once the set switching point is reached until it is reset manually using a push-button. However, the thermostat can only be reset once it has cooled down by a switching difference of approx. 2 kelvin. Resetting the device by isolating it from the voltage supply is also possible.