Function Description; Boiler Temperature Control - Viessmann Vitotronic 200 KW2 Installation And Service Instructions Manual

Function description

Boiler temperature control

Brief description
The boiler water temperature is
regulated by starting and shutting
down the burner.
In the delivered condition, the
switching differential is ±2 K, relative
to the current set value.
The set boiler water temperature
depends on the boiler and the
heating/control versions installed. It
is calculated from the set flow
temperatures of the heating circuit
without mixer, the mixer circuit and
the set DHW temperature.
When the DHW cylinder is heated
up, a set boiler water temperature is
Functions
The boiler water temperature is
recorded by three sensors
separately:
H High limit safety cut−out STB
(liquid expansion)
H Control thermostat TR
(liquid expansion)
H Boiler temperature sensor KTS
(change in resistance PT 500)
Upper control limits
H High limit safety cut−out
STB 110/100/95 ºC
H Control thermostat TR 75/87/95 ºC
H Electronic maximum limit
Setting range: 20 to 130 ºC, change
via coding address 06.
This limit is only effective within
the control range (not for DHW
cylinder heating).
46
applied, which lies 20 K above the
set DHW cylinder value (adjustable
via coding address 60). The boiler
water temperature is limited by
control thermostat TR.
The actual boiler water temperature
is required for the control of the
heating circuits and the DHW
cylinder.
Coding addresses which influence
the boiler temperature control
02, 04, 06, 13.
For a description, see the coding
overview.
Lower control limits
H Ultra low temperature boiler:
At an outside temperature of 1 ºC,
the boiler water temperature will
be regulated to at least 15/22 ºC
(frost protection).
H Low temperature boiler:
Controls the boiler water
temperature in standard mode and
frost protection to 35/42 ºC. For
changes, see coding address A3
(variable frost limit).