8.7
Automatic summer time/winter time changeover
The clock is automatically adjusted on the last Sunday in March at 2.00h and on the last Sunday
in October at 3.00h.
Function
WE
Configuration
Summer time/winter time changeover
ON
Co5 -> Fb05 = ON
8.8
Frost protection
To protect the system from freezing up, the flow temperature or return flow temperature are
monitored.
Note!
The frost protection function is not activated when manual mode is selected at the mode switch.
Flow temperature monitoring
The flow temperature cannot drop enough to cause the pipes to freeze when the controller is in
rated or reduced operation. In stand-by mode, the flow temperature is not regulated. Therefore,
it is monitored. Should the flow temperature fall below 3 °C, the flow temperature is restricted to
the minimum return flow temperature.
Return flow temperature monitoring
The outdoor temperature is monitored at the input AF (outdoor sensor) or at the input AE2 (0 to
10 V signal). In both cases, the
Frost protection limit (–30 to 30 °C, WE: 3 °C with Co5 -> Fb00
= ON) must be defined to monitor this parameter.
Alternatively, a frost protection thermostat can also be used for monitoring. This requires input
AF to be configured as a binary input (BE11) (Co5 -> Fb00 = OFF, FroSt).
If there is no boiler in operation and the outdoor temperature falls below the frost protection
limit or if the binary input of the frost protection thermostat is active, the pumps are activated
and the valves opened. As a result, the system or individual parts of the system cannot freeze.
Function
WE
Configuration
Outdoor sensor
ON
Co5 -> Fb00
EB 5474 EN
55
System-wide functions
