CFA - Electronic frost protection alarm

CFA is connected to a temperature sensor that measures the water temperature in the heating coil. The water temperature in the heating coil is normally regulated by another regulator/DUC with the control signal (0-10 or 10-0V) connected via CFA to the control valve. If the water temperature in the coil drops without any response from the regulator / DUC, CFA starts regulating the control valve.