Parameter
WE
Adjustment range
Vorrangschaltung
(priority operation) = EIN (on)
AUS
AUS (off), EIN (on)
6.2
Thermal disinfection
In all systems with DHW heating, the DHW storage tank is thermally disinfected on a selected
day of the week or every day. The storage tank is heated up to the adjusted
Disinfection
temperature
. The load set point is always 5 °C higher than the disinfection temperature. The
process starts at the beginning of the time-of-use and ends at the lastest when the time-of-use
ends.
Thermal disinfection for preventing legionella infection causes:
4
excessively high return flow temperatures during the disinfection cycle (return flow tempe-
rature limitation suspended)
4
excessively high storage temperatures after thermal disinfection has been concluded,
4
lime scale (possibly), which can have a negative effect on heat exchanger performance.
Note:
The programming of the times-of-use is described in detail in section 1.7.
2
[Übersicht > Parameter > Warmwasserbereitung]
Parameter
WE
Adjustment range
Desinfektionstemperatur
(disinfection temperature)
70 °C
50 to 80 °C
NZ therm. Desinfektion
(times-of-use for thermal disin-
fection)
7:00 to 22:00
As required
6.3
External demand for DHW
This function causes the controller to switch to DHW demand when the binary input WWA
(UE2) is closed. If an external demand for DHW and thermal disinfection occur at the same time,
thermal disinfection has priority.
2
[Übersicht > Parameter > Warmwasserbereitung]
34
EB 5571-2 EN
Functions of DHW heating
