Dhw Tank Control - Viessmann VITOTRONIC 100 GC1B Installation And Service Instructions Manual

Function Description

DHW Tank Control

Brief Description
The DHW tank adjustable high limit functions as a
constant temperature controller. This is achieved by
starting and stopping the circulation pump for DHW
tank heating.
The switching differential is ±2.5 K.
For heating the DHW tank, a set boiler water
temperature is defaulted that lies 20 K above the set
DHW temperature (change in coding address "60"
in category 3 "DHW").
During DHW tank heating, central heating is switched
off (optional DHW tank priority control).
Functions
Frost Protection
The DHW tank will be heated to 68ºF (20ºC) if the DHW
temperature falls below 41ºF (5ºC).
Auxiliary Function for DHW Heating
This function is activated by providing a second set
DHW temperature via coding address "58" in category 3
"DHW" and activating the fourth DHW phase for DHW
heating.
Set DHW Temperature
The set DHW temperature can be adjusted between
50/140ºF (10/60ºC).
The set range can be extended up to 203ºF (95ºC) via
coding address "56" in category 3 "DHW".
System With Primary Store
The above functions also apply in conjunction with
primary store systems.
Set the following codes: "4C:1", "4E:2" in category
1 "General", "55:3" in category 3 "DHW" (see coding
overview).
System With Solar DHW Heating
A third set DHW temperature can be defaulted via coding
address "67" in category 3 "DHW".
Reheating by the boiler will be suppressed above this
value. The DHW tank is heated exclusively by the solar
thermal system.
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Vitotronic 100, GC1B Installation and Service
Control Sequence
Coding "55:0" in Category 3 "DHW", tank Heating
The DHW tank Goes Cold (set value −2.5 K; change via
coding address "59" in category 3 "DHW"):
The set boiler water temperature is adjusted 20 K
higher than the set DHW temperature (adjustable via
coding address "60").
Pump on:
– Starting the circulation pump for DHW tank heating
subject to the boiler water temperature (code "61:0"):
The circulation pump starts when the boiler water
temperature is 7 K higher than the DHW temperature.
– Immediate start of the circulation pump for DHW tank
heating (code "61:1").
The DHW tank is Hot (set value +2.5 K):
The set boiler water temperature is returned to the
selected set value.
Pump run-on:
The circulation pump runs on after DHW tank heating
until one of the following criteria is met:
– The differential between the boiler water and the
DHW temperature is less than 7 K.
– The weather-compensated set flow temperature
has been reached.
– The set DHW temperature is exceeded by 5 K.
– The set max. run-on time has been reached (coding
address "62").
Without pump run-on (code "62:0")
Coding "55:1" in Category 3 "DHW", Adaptive DHW tank
Heating
With adaptive DHW tank heating, the speed of the
temperature rise during DHW heating is taken into
account.