Boiler Water Temperature Control; Cylinder Temperature Control - Viessmann Vitotronic 100 Installation And Service Instructions Manual

Boiler water temperature control

The switching hysteresis, i.e. the burner runtime, var-
ies subject to the current heat demand.
ERB50 function
Code "04:1"
Depending on the heat demand, values between 6 and
12 K result.
ON
OFF
+9
+3
set
-3
low average
heat demand heat demand
Fig. 36
Control sequence
Boiler goes cold
(Set value 2 K)
–
The burner start signal is set for a set boiler water tem-
perature 2 K and the burner starts its own monitoring
−
program.
The burner start may be delayed by a few minutes,
depending on the number of auxiliary circuits and the
combustion type.

Cylinder temperature control

Brief description
The cylinder thermostat functions as a constant tem-
■
perature controller. This is achieved by starting and
stopping the circulation pump for cylinder heating.
The switching differential is
■ When the DHW cylinder is heated, the default set
boiler water temperature is 20 K above the set DHW
temperature (adjustable via coding address "60" in
group 3 "DHW").
Functions
Priority control
■ With priority control: (code "A2:2" in group 5 "Heating
circuit"):
During cylinder heating, the set flow temperature is
set to 0 C.
º
The heating circuit pump is switched off.
Without priority control:
■
The heating circuit pump continues to run.
(cont.)
Time
high
heat demand
2.5 K.
±
ERB80 function
Code "04:2"
Depending on the heat demand, values between 6 and
20 K result.
ON
OFF
+17
+3
set
-3
low average
heat demand heat demand
Fig. 37
Boiler heats up
(Set value +2 K)
The burner shuts down.
Frost protection function
If the DHW temperature falls below 5 °C, the DHW cyl-
inder is heated to 20 °C.
Set DHW temperature
The set DHW temperature can be adjusted between
10 and 60 °C.
Function description
Time
high
heat demand
63