Viessmann Vitotronic 100 GC1 Installation And Service Instructions Manual page 116

Function description – Vitotronic 300-K, MW1S
Heating circuit control
Supply temperature control
Differential temperature:
The differential temperature may be
adjusted via coding address 9F; factory
supplied setting 8 ˚C / 15 ˚F .
The differential temperature is that
minimum temperature differential by
which the common supply temperature
should be higher than the currently
required supply temperature of the
mixing valve circuit.
System with only one mixing valve
circuit:
The common set supply temperature
will be automatically held 8 ˚C /
15 ˚F above the set supply
temperature of the mixing valve
circuits.
System with high temperature
(boiler) circuits and mixing valve
circuits:
The common set supply temperature
operates in accordance with its own
heating curve. The differential
temperature of 8 K towards the set
supply temperature of the mixing
valve circuits is set up at the factory.
Upper control limit
Electronic maximum limit
Setting range: 1 to 127 ˚C /
34 to 261 ˚F
Changes via coding address C6.
Please note:
The maximum limit is no replacement
for the underfloor heating system
temperature limiter.
Control sequence
Mixing valve circuit
The mixing valve motor will not be
activated within the neutral zone
(±1 ˚C / 2 ˚F).
116
(cont.)
110
230
87
189
+20/ 68
Outdoor temperature in °C / °F
A Max. common supply temperature
B Slope = 1.8 high temperature
(boiler) circuit
C Slope = 1.2 mixing valve circuit
D Common supply temperature (at
a differential temperature = 8 ˚C/
15˚F )
E Minimum common supply
temperature
Lower control range limit
Electronic minimum limit
Setting range: 1 to 127 ˚C /
34 to 261 ˚F
Changes via coding address C5
(only effective in standard mode)
Supply temperature falls
(set value –1 ˚C / -2 ˚F)
The mixing valve motor receives
the open signal.
The signal duration lengthens with
an increasing control differential.
The duration of pauses reduces with
an increasing control differential.
8K
-20/-4
Supply temperature rises
(set value +1 ˚C / 2 ˚F)
The mixing valve motor receives
the close signal.
The signal duration lengthens with
an increasing control differential.
The duration of pauses reduces
with an increasing control differential.