Function Block "D.h.w. Storage Tank; Operating Lines; Charging; Charging With Hot Water - Siemens RVL471 Basic Documentation

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Siemens Building Technologies
HVAC Products
19

Function block "D.h.w. storage tank"

Based on the settings made, this function block performs all d.h.w. functions required
for the plant types with a d.h.w. storage tank.
With plant types x–5 (electric immersion heater only ), this function block is not active
since the electric immersion heater provides the functions independent of the RVL471.

19.1 Operating lines

Line Function, parameter
125 D.h.w. charging
D.h.w. temperature sensor / control thermostat
126
127 D.h.w. charging temperature boost
128 Switching differential of the d.h.w. temperature
129 Maximum d.h.w. charging time
130 Setpoint of the legionella function
131 Forced charging
19.2 D.h.w. charging
The type of d.h.w. charging is to be entered on operating line 125. There are 2 basic
choices:
• D.h.w. charging with hot water
• D.h.w. charging alternately with hot water and the electric immersion heater
19.2.1 D.h.w. charging with hot water
The setting on operating line 125 is 0.
The d.h.w. storage tank is charged exclusively with hot water throughout the year.
19.2.2

Alternate d.h.w. charging with hot water and electricity

The setting on operating line 125 is 1, 2, or 3.
In the winter, the d.h.w. storage tank is charged with hot water from the heating system
and, in the summer, with the electric immersion heater.
Changeover takes place based on the following criteria:
• Changeover from hot water charging to the electric immersion heater takes place if
there has been no demand for space heating for at least 48 hours (changeover at mid-
night)
• Changeover from the electric immersion heater to hot water charging is effected when
there is a demand for space heating. Depending on the setting made on operating line
125 (1, 2, or 3), different types of heat demand are considered for the changeover cri-
terion:
Operating line 125
1
2
3
Basic Documentation RVL471
19 Function block "D.h.w. storage tank"
Criterion for changeover
Demand for space heating from own heating circuit
Demand for space heating from all controllers connected to
the data bus (LPB), having the same segment number,
including those from the own heating circuit
Demand for space heating from all controllers connected to
the data bus (LPB), including those from the own heating
circuit
Unit Factory Range
setting
0 0...3
0 0...3
°C 10 0...50
°C 8 1...20
min 60 --- / 5...250
°C --- --- / 20...100
0 0 / 1
CE1P2524E
23.10.2002