Siemens RVL471 - Boost of the D.h.w. Charging Temperature; Maximum D.h.w. Charging Time; Setpoint of Legionella Function

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Siemens Building Technologies Basic Documentation RVL471 CE1P2524E
HVAC Products 19 Function block "D.h.w. storage tank" 23.10.2002
19.4 Boost of the d.h.w. charging temperature
The boost of the d.h.w. charging temperature in °C can be set on operating line 127.
The boost refers to the setpoint of the d.h.w. temperature.
The lower the setting of this value, the longer d.h.w. charging takes.
T
Lw
[°C] = T
BWw
+ T
BW∆
Example:
Setpoint of d.h.w. temperature (T
BWw
, operating line 26) = 50 °C
Boost of the d.h.w. charging temperature (T
BW∆
, operating
line 127)
= 10 °C
Resulting setpoint of the charging temperature T
Lw
= 60 °C
If thermostats are used, the boost of the d.h.w. charging temperature must still be set.
19.5 Maximum d.h.w. charging time
The maximum charging time for d.h.w. storage tanks can be set on operating line 129.
This function is always active, independent of the kind of d.h.w. priority (absolute, shift-
ing, or parallel).
As soon as d.h.w. charging starts, a counter records the charging time. If charging is
terminated before the set maximum charging time has expired, the counter will be set
to zero. A new charging cycle can commence at any time.
However, if charging takes longer than the set maximum time, charging will be stopped
and than locked for the same period of time. Then, charging will be resumed either until
the setpoint is reached or maximum limitation terminates the charging time again.
This function can be deactivated, in which case the charging time will not be limited.
B
WL
t
2524D03
ON
OFF
t
T
BWw
T
BW
T
BWw
- SD
BW
t
Lmax
t
Lmax
D.h.w. charging locked
B
WL
D.h.w. charging
ON D.h.w. charging ON
OFF D.h.w charging OFF
tTime
t
Lmax
Maximum charging time
T
BW
D.h.w. temperature
TBWw D.h.w temperature setpoint
SDBW Switching differential d.h.w.
19.6 Setpoint of legionella function
On operating line 130, the setpoint of the legionella function can be adjusted or the
function deactivated. This function raises the d.h.w. temperature periodically, thus
making certain that legionella viruses will be killed. For description, refer to chapter
"23 Function block "Legionella function"