FTD 011 is two thermostats in the same casing. Available with one NO contact and one NC contact or with two NO contacts.
Normally closed - Contact breaks (red casing) for regulating heaters or for switching signal devices when temperature has fallen below the minimum value. The contact opens when temperature is rising.
Normally open - Contact makes(blue casing) for regulating filter fans, heat exchangers, cooling devices or for switching signal devices when temperature limit has been exceeded. The contact closes when temperaure is rising.
The thermostat with one NO contact and one NC contact is used, for example, for controlling both a heater and fan.
The thermostat has two NO contacts, good for controlling two fans. One of the thermostats activates first and a smaller fan, for example, is activated. If this fan is unable to cool sufficiently and the temperature thus increases, the other thermostat activates and a larger fan can be started.
