Functions - Viessmann VITOTRONIC 300 Installation And Service Instructions Manual

DHW heating control (cylinder temperature...

Functions

Time program
An automatic program or an individual time program
may be selected for DHW heating and the DHW circu-
lation 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 pha-
ses per day to be set for DHW heating and the DHW
circulation pump.
All started DHW heating sequences are completed
irrespective of the time program.
In conjunction with parameter "7F" in the "Gen-
eral" group
■ Detached house
Parameter "7F:1":
– Automatic mode
The heating times for heating circuit 1 are applied
to systems with 2 or 3 heating circuits.
Individual time program
–
The time phases for DHW heating and the DHW
circulation pump have the same effect on all heat-
ing circuits.
■ Apartment building
Parameter "7F:0":
Automatic mode
–
For systems with 2 or 3 heating circuits, the heat-
ing times for the respective heating circuit will be
applied.
– Individual time program
The time phases for DHW heating and the DHW
circulation pump can be adjusted individually for
each heating circuit.
Priority control
■ With priority control: (Parameter "02:2" in the "Heat-
ing circuit..." group):
The set flow temperature is adjusted to 0 °C during
DHW heating.
The mixer closes and the heating circuit pump is
switched off.
■ Without priority control:
The heating circuit control unit continues to operate
with the same set value.
The set flow temperature is determined from the fol-
lowing parameters:
– Outside temperature
– Differential between the set and the actual boiler
water temperature
Heating curve slope and level
–
Setting of parameter "02" in the "Heating cir-
–
cuit..." group
System function description
(cont.)
Frost protection
The DHW cylinder will be heated to 20 °C if the DHW
temperature falls below 5 °C.
Additional function for increased DHW heating
This function is activated by providing a 2nd set cylin-
der temperature in parameter "03" in the "DHW" group
and activating the 4th time phase in the DHW time pro-
gram for DHW heating.
Set DHW temperature
The set DHW temperature can be adjusted between
10 and 60 °C.
Parameter "01" in the "DHW" group enables the set
range to be extended to 95 °C.
Parameter "0B" in the "DHW" group enables the set
value of the programming unit and/or remote controls
to be assigned.
DHW circulation pump
This delivers hot water to the draw-off points at adjust-
able times.
4 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 oper-
ating program: See parameter "1F" in the "Heating
circuit..." group.
System with cylinder loading system
The above functions also apply in conjunction with cyl-
inder loading systems.
Set the following parameters:
"00:3" in the "DHW" group; "53:1", "55:2" in the "Gen-
eral" group.
System with solar control unit
A 3rd set DHW temperature can be assigned at
parameter "0C" in the "DHW" group.
The DHW cylinder is only reheated by the boiler if the
temperature falls below this value.
143