Especially suited to ensure the protection of hot water coil heating systems against freezing. The frost protection thermostat models JTF-21 to JTF-25 are equipped with two switching outputs that provide the option to act on the system already in advance of the attaining of the corresponding danger point. All devices are fail-safe and dispose of a lead-sealable set value setting facility. With the exception of the JTF-3 / JTF-4, the capillaries are active over their entire length. The device responds if the adjusted scale
value is attained over a length of approx. 30 cm 60 cm respectively (with 12 m variants).