System Layouts - Viessmann SCU345 Manual

2.6

System layouts

System 1
2-tank system with valve logic, 1 pump, 3 sensors and 3-port valve
The controller compares the temperature at sensor
S1 to the temperatures at sensors S2 and S4. If the
measured temperature differences are higher than
the adjusted switch-on temperature differences, the
Note: 3-port valve normally open - tank 1 (S2)
pump (R1) will be activated and the corresponding
tank will be loaded up to the adjusted maximum
temperature via the valve (R3). Tank 1 is loaded with
priority.
Sensor/
Designation Description
terminal
S1 TCOL Temperature collector
S2 TST1B Temperature tank 1 bottom
S3 Optional sensor for measure-
ment purposes or options
S4 TST2B Temperature tank 2 bottom
S5 Optional sensor for measure-
ment purposes or options
V40
Relay Description
R1 Solar pump
R2/R4 optional:
Thermal disinfection
Parallel relay
Heat dump
R3 3-port valve tank 1/2
7