Dhw Tank Temperature Control - Viessmann VITOTRONIC 200 Installation And Service Instructions Manual

Vitotronic 200, HO1B and 300-K, MW2C Installation/Service

DHW Tank Temperature Control

Brief description
H The tank temperature control is a constant temperature
control function. This is achieved by starting and
stopping the circulation pump for tank
heating. The switching differential is 5°F (±2.5 K).
H When the DHW tank is heated, a set supply
temperature is specified that is 36°F (20 K) higher than
the set DHW temperature (adjustable at coding "60" in
the "DHW" group).
Functions
Time program
An automatic or an individual time program may be
selected for DHW heating and the DHW recirculation
pump.
Compared with the heating circuit heat up phase, DHW
heating starts 30 min earlier in automatic mode.
The individual time program enables up to 4 time
phases per day to be set for DHW heating and the DHW
recirculation pump for every day of the week.
All tank heating sequences will be completed
independently of the time program.
In conjunction with coding "7f" in the "General" group
H Detached house
Coding "7f:1":
– Automatic operation
The heating times for heating circuit 1 are applied
to systems with two or three heating circuits.
– Individual time program
The time phases for DHW heating and the DHW
recirculation pump have the same effect on all
heating circuits.
H Apartment building
Coding "7f:0":
– Automatic mode
For systems with two or three heating circuits,
the heating times for the respective heating circuit
will be applied.
– Individual time program
The time phases for DHW heating and the DHW
recirculation pump can be adjusted individually for
each heating circuit.
Function Description, Vitotronic 200/300-K
Priority control
H With priority control: (coding "a2:2" in the "Heating
circuit..." group):
During tank heating, the set supply temperature
is set to 32°F (0°C).
The mixing valve closes and the heating circuit pump is
switched off.
H Without priority control:
The heating circuit control unit continues to operate
with the same set value.
Frost protection
The DHW tank will be heated to 68°F (20°C) if the DHW
temperature sinks below 41°F (5ºC).
Auxiliary function for DHW heating
This function is activated by providing a second set DHW
temperature at coding "58" in the "DHW" group and
activating the fourth DHW phase for DHW heating.
Set DHW temperature
The set DHW temperature can be set between 50 and 140°F
(10 and 60°C).
The set value range can be extended to 203°F (95ºC) at
coding "56" in the "DHW" group.
The default set value can be assigned to the programming
unit and/or Vitotronic 300A remote control at coding
"66" in the "DHW" group.
DHW recirculation pump
This delivers hot water to the draw-off points at
adjustable times. Four time phases can be selected at
the control unit for every day.
Auxiliary circuits
DHW heating in conjunction with the heating circuits can
be disabled or enabled by changing over the operating
program (see coding "d5" in the "Heating circuit..."
group).
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