7
System-wide functions
7.1 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
7.2 Frost protection
The
Frost protection
function does not work in manual mode.
The heating system is automatically monitored for frost protection. The operation of a pump, a
heating circuit or DHW circuit as a frost protection measure is indicated by
on the display. If
the outdoor temperature drops below 0 °C, the heating and circulation pumps are activated.
The DHW storage tank is charged to 10 °C.
7.3 Forced operation of the pumps
When the heating circuit pumps have not been activated for 24 hours, forced operation of the
pumps is started between 12.00h and 12.01h. This is done to avoid that the pumps get stuck
when they are not operated for a longer period of time. The forced operation of the storage tank
or heat exchanger charging pump is operated between 12.01h and 12.02h.
7.4 Return flow temperature limitation
The temperature difference between the flow and return flow indicates how well the energy is
used: the greater the difference, the higher the efficiency. A return flow sensor is sufficient to
evaluate the temperature difference when the flow temperatures are preset. The return flow tem-
perature can be limited either to a value depending on the outdoor temperature (variable) or to
a fixed set point.
When the temperature measured at return flow sensor RüF exceeds the
Limitation factor, the set
point of the flow temperature (flow temperature of the heating system, charging temperature) is
reduced. As a result, the primary flow rate is reduced and the return flow temperature falls. The
set point reading (flow temperature of the heating system, charging temperature) blinks to indi-
cate that a return flow limitation is active.
EB 5179 EN
59
System-wide functions
