Viessmann VITOTRONIC 100 Installation And Service Instructions Manual page 34

Heating system designs
System version 10
Codes must be set on every Vitotronic 100.
Required coding
01 : 2 Multi−boiler system with cascade control via LON BUS
01 : 3 Multi−boiler system with external cascade control via switching
contacts
02 : 2 Modulating burner operation
03 : 1 Oil fired operation (irreversible)
0C : 1 Constant return temperature control
Boiler circuit pump on plug sL
4d : 2
Automatic changeover
Connecting temperature sensor T1 to plug aJA
4A: 1
Possible applications
For example, older systems or
systems in nurseries where the
hydraulic conditions cannot be
clearly defined and/or systems
where downstream heating circuits
cannot be controlled.
The cascade and cylinder control
must be provided by a higher control
unit.
*1
If required.
34
(cont.)
*1
*1
Temperature sensor T1 closes the
three−way mixing valve in proportion
and therefore ensures boiler
protection if the required minimum
return temperature is not achieved.
Boiler and downstream heating
circuits are hydraulically coupled
together. The flow temperature is
controlled by the temperature sensor
(cascade control unit) in the low loss
header.
Note
Size the boiler circuit pumps for each
boiler so that their volume flow is at
least as large as the max. total
heating circuit volume flow.
Recommendation: 110 %