Viessmann SCU345 Manual page 19

System 5
3-tank solar system with valve logic and priority logic
The controller compares the temperature at sensor
S1 to the temperatures at sensors S2, S4 and S5. If
the measured temperature differences are higher than
the adjusted switch-on temperature differences, the
Ventillogik
pump (R1) will be activated and the corresponding
tank will be loaded up to the adjusted maximum tem-
perature via the valves (R3, R4). In this system, the
desired tank sequence can be adjusted. Depending on
Ventillogik
1
2
the valve type used, the corresponding valve logic has
to be selected.
Sensor/
terminal
S1
S2
S3
S4
S5
V40
Relay
R1
R2
R3
R4
Valve logic
Ventillogik
1
Flow direction when the
Durchflussrichtung
2
valve is normally open im stromlosen Zustand
Durchflussrichtung
3
im stromlosen Zustand
Designation Description
TCOL Temperature collector
TST1B Temperature tank 1 bottom
Optional sensor for measure-
ment purposes or options
TST2B Temperature tank 2 bottom
TST3B Temperature tank 3 bottom
Optional sensor for measure-
ment purposes or options
Description
Solar pump tank 1
Valve tank 1/2, 3
Valve tank 2/3
1
2
3
4
Durchflussr
im stromlo
19