In case of a secondary pump failure, the heat exchanger could easily overheat and trigger a maximum temperature or safety temperature thermostat alarm.
To avoid this, connect the common alarm output of a pump macro to the input “SecPmpStatAlm”.
If this alarm is active the heat exchanger will reduce its heat demand to the minimum value of the actual heat demand and the parameter DST-03. If the minimum value is below SST-02 always the min supply temperature defined at parameter SST-02 is valid.
See the connection examples in the next figure.
Fig. 15. Connect the pump status or alarm to the heat exchanger macro