Viessmann Vitotronic 100 GC1 Installation And Service Instructions Manual page 118

Function description – Vitotronic 300-K, MW1S
DHW tank temperature control
Control sequence
Pump delay
The DHW pump continuous operation
(coding 62 : 10) after the DHW tank
heating, until
– the difference between the boiler
water and the DHW temperature
is less than 7 ˚C / 13 ˚F or
– the common supply temperature
is achieved based on outdoor reset
calculations or
– the actual temperature is 5 ˚C /
9 ˚F higher than the set DHW
temperature or
– the maximum time delay (adjustable
via coding address 62) has been
reached.
Without the pump time-delay for
DHW tank heating
(coding 62 : 0)
Coding 55 : 0:
DHW heating
The DHW tank goes cold
(set value –2.5 ˚C / 4.5 ˚F, adjustable
via coding address 59)
The common supply temperature is
adjusted 20 ˚C / 36 ˚F higher than the
set DHW (adjustable via coding address
60).
The DHW tank is hot
(set value +2.5 ˚C / 4.5 ˚F)
The common set supply temperature
is returned to the weather-
compensated value.
118
(cont.)
Coding 55 : 1:
Adaptive DHW tank heating
With adaptive DHW tank heating, the
speed of the temperature rise during
DHW heating is taken into account.
Also taken into account is the question
of whether the boiler will be required to
supply heat after the DHW tank has
been heated or whether residual boiler
heat should be transferred to the DHW
tank.
Accordingly, the control unit
determines the burner and DHW
recirculation pump shutdown point
to prevent the set DHW temperature
being substantially exceeded after the
DHW tank has been heated.
Coding 55 : 2:
DHW tank temperature control with
2 DHW tank temperature sensors
st
The 1 DHW tank temperature sensor
enables the DHW pump, and is
evaluated for stop conditions during
the pump run-on time. The 2
tank temperature sensor (inside the
cold water inlet) is designed to
prematurely start DHW tank heating
when large quantities of DHW are
drawn off as well as to prematurely
stop DHW tank heating if no DHW
is drawn.
Coding 55 : 3:
DHW tank control – DHW heating (for
DHW heating systems only)
The DHW tank goes cold
(set value –2.5 ˚C / -4.5 ˚F, adjustable
via coding address 59),
The common set supply temperature
is adjusted 20 ˚C / 36 ˚F higher than
the set DHW temperature (adjustable
via coding address 60).
The primary DHW pump is switched
ON.
The three-way mixing valve opens
and then regulates to the defaulted
set value.
The DHW pump cycles (short term
ON and OFF) until the set supply
temperature has been reached, then
it runs constantly. If, during DHW
tank heating, the actual value stays
below the required set supply
temperature, then the DHW pump
will temporarily cycle again.
The DHW tank is hot
st
(1 DHW tank temperature sensor:
Actual value ≥ set value
nd
DHW and
nd
2 DHW tank temperature sensor:
Actual value > set value –1.5 ˚C /
-2.7 ˚F)
the common set supply temperature
is returned to the weather-
compensated value;
the DHW pump
– is immediately switched OFF, if
the three-way mixing valve is open
or
– is switched OFF after run-on time
adjustable via coding 62.