6
Figure 4: Configuration of electric frost protection heater with PTC heating element
3.1.1.2 Electric frost protection heater with resistance heating element
The electric frost protection heater with resistance heating element has to be run with a digital flow
indicator STR. The digital flow indicator is either part of the module or has to be installed separately in the
intake air duct with a straight flow distance of 5 x DN.
The electric frost protection heater with resistance heating element is only
activated if the enabling contact STR is closed, so that the flow indicator detects an
air flow through the electric frost protection heater!
The combination of switch settings of the DIP switch S2, the terminal configuration X1 and X2 for control
of the electric defroster heater with resistance heating element is shown in figure 5.