200/218
Siemens Building Technologies
Basic Documentation RVA63.242, RVA53.242
CE1P2373E
Landis & Staefa Division
General control processes
26.03.2001
6.14.3 For the heating circuit
Frost protection for the heating circuit is active with both types of application, pump
heating circuit and mixing heating circuit. If the flow temperature of the heating circuit
falls below 5 °C, a valid temperature demand of 10 °C will be generated. This causes
the heating circuit pump to be activated and – in case of the mixing heating circuit – the
mixing valve actuator to be driven to the required position.
If the flow temperature reaches the switch-off threshold of 7 °C, the temperature
demand will be maintained for another 5 minutes. This ensures that the hot water will
reach the entire heating circuit including the return.