Viessmann Vitoligno 300-P Service Instructions For Contractors page 106

Function description
Control functions
Flow temperature control
110
85
D
50
+20
Outside temperature in ºC
A Max. boiler water temperature
B Slope = 1.8 for heating circuit 1 with
mixer M1
C Slope = 0.6 for heating circuit 2 with
mixer M2
Level = 10
D Boiler water temperature (at a dif-
ferential temperature = 8 K)
E Minimum boiler water temperature,
defaulted by the boiler coding card
Upper control limit
Electronic maximum temperature limiter
Setting range: 1 to 127 ºC,
Changes via coding address "C6".
Note
The maximum temperature limit is no
substitute for the underfloor heating sys-
tem temperature limiter.
Temperature limiter for underfloor heat-
ing:
106
(cont.)
B
A
C
E
-20
Differential temperature:
The differential temperature can be
adjusted via coding address "9F",
Delivered condition: 8 K.
The differential temperature is that mini-
mum value, by which the boiler water
temperature should be higher than the
highest currently required mixer circuit
flow temperature.
■ System with one or two heating circuits
with mixer:
The set boiler water temperature will
be automatically held 8 K above the
set flow temperature.
The temperature limiter switches the
heating circuit pump OFF if the set value
has been exceeded. In such cases, the
flow temperature reduces only slowly,
i.e. it may be several hours before the
system restarts again automatically.
Lower control range limit
Electronic minimum temperature limit
Setting range: 1 to 127 ºC
Changes via coding address "C5".
Only enabled during operation with
standard room temperature.