Viessmann Vitotronic 100 GC1 Installation And Service Instructions Manual page 112

Function description – Vitotronic 300-K, MW1S
Cascade control
(cont.)
Net calorific strategy 2 (coding 3C : 2)
Start-up
100
50
33
0
100
50
0
200
150
100
33
0
Boiler sequence
The boiler sequence is determined by
the boiler sequence selection and the
following coding addresses (see also
page 152):
38 Changing the lead boiler and the
boiler sequence
st
38 : 1 Every 1 day of the
month, the boiler with
the burner which has
operated for the shortest
number of hours becomes
lead boiler
38 : 2 After 200 to 20000
run hours, the boiler with
the next higher number
(coding address 07 of
Vitotronic 100) becomes
lead boiler
112
Switching OFF
100
66
33
0
100
33
0
200
150
100
33
0
Time
39 Boiler 1, 2, 3 or 4 permanent
lead boiler
3A Boiler 1, 2, 3 or 4 permanent
last boiler
41 ECO threshold boiler 1
42 ECO threshold boiler 2
43 ECO threshold boiler 3
44 ECO threshold boiler 4
Via the ECO threshold, every boiler
can be blocked or enabled subject to
the outdoor temperature. The ECO
control becomes disabled, if the boiler
is required to achieve the set supply
temperature, when enabled boilers
have failed. At least the lead boiler
remains active if all boilers in a system
are blocked by the ECO control.
Time