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Siemens Building Technologies Basic Documentation RVD110, RVD130 CE1P2381E
HVAC Products 15 Function block Extra legionella functions 27.05.2004
15 Function block Extra legionella func-
tions
In d.h.w. systems with storage tanks, the legionella function ensures that legionella
viruses will not occur. This is accomplished by periodically raising the d.h.w. tempera-
ture in the storage tank.
15.1 Operating lines
Line Function, parameter Unit Factory
setting
Range
104
Legionella function
6 --- , 1…7, 1-7
105
Setpoint of legionella function
°C 65 60…95
126
Time of legionella function
hh:mm --:-- --:--,
00:00…23.50
127
Dwelling time at legionella setpoint
min --- ---, 10…360
128
Circulating pump operation during legionella function
1 0 / 1
157 Maximum setpoint of the return temperature with d.h.w. heat-
ing at the legionella setpoint
°C ---
---,
0…140 °C
15.1.1 Legionella function
If and when the legionella function shall be activated is to be set on operating line104.
The legionella function can be started when the d.h.w. temperature is at the nominal
setpoint (button for d.h.w. heating is lit and no holidays are active). The function will be
deactivated when the frost level is reached.
The legionella function can be aborted by pressing the button for d.h.w. heating.
15.1.2 Setpoint
The legionella setpoint can be adjusted in the range from 60…95 °C (operating
line105). In the case of storage tanks with 2 sensors, the d.h.w. temperature must
reach the setpoint at both sensors.
15.1.3 Time
The legionella function is started at the set time. If no time has been set (operating line
126 =
--:--), the legionella function will be started with the first d.h.w. release at the nominal
setpoint.
If the legionella function cannot be performed at the set time because d.h.w. heating
has been deactivated (button for d.h.w. heating, holidays), it will be activated as soon
as d.h.w. heating is released again.
In the case of d.h.w. heating with flow switch, the legionella function will be activated at
the set time, but the legionella viruses will only be killed the next time d.h.w. is con-
sumed.
15.1.4 Dwelling time
The legionella setpoint must be maintained for at least the set dwelling time.
If the lower storage tank temperature rises above the legionella setpoint minus 1 K, the
legionella function is considered completed and the dwelling has elapsed.
If the storage tank temperature falls by more than SD + 2 K (switching differential plus
2 K) below the legionella setpoint before the dwelling time has elapsed, the dwelling
time must again be completed.
If no dwelling time has been set (operating line 127 =
---), the legionella function will be
performed the moment the legionella setpoint is reached.
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