Viessmann VITOLIGNO 300-P Service Instructions Manual page 116

Function description
Control functions
■ The mixer has been closed for 12 min
(mixer economy function, coding
address "A7").
■ The actual room temperature exceeds
the value selected via coding address
"B5".
System dynamics, mixer circuit
In conjunction with heating circuits 1 and
2:
You can influence the control character-
istics of the mixer via coding address
"C4".
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,
specified by the boiler coding card
116
(cont.)
B
A
C
E
-20
Frost protection
In the case of outside temperatures
below +1 ºC, a minimum flow tempera-
ture of 10 ºC is ensured. For changes
see coding address "A3", variable frost
limit.
Differential temperature:
The differential temperature can be
adjusted via coding address "9F".
Delivered condition: 8 K.
The differential temperature is the 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.