Viessmann Vitodens 200 Technical Manual page 43

Standby instantaneous water heater (Vitodens 300, gas fired combi boiler)
An electronically regulated standby
instantaneous water heater is integrated
into the Vitodens 300.
Specification standby instantaneous water heater
Capacity
DHW side
Heating water side
Connections
Hot and cold water
Max. operating pressure
Output
Rated output range
of the gas fired combi boiler
Continuous DHW output
for heating DHW from 10 ºC to
45 ºC and an average heating
water temperature of 70 ºC
Drawing rate
Outlet temperature,
adjustable
DHW temperature subject to volume flow
65
60
55
50
45
D
40
35
6 6.5 7 7.5 8 8.5
Volume flow at the tap (mixed water volume) in l/min
VITODENS
When the comfort function is switched
ON, the temperature of the instantaneous
water heater will be maintained.
litres
litres
G (male thread)
bar
kW
kW
litres/h
litres/minute
ºC
B
9 9.5 10 10.5 11 11.5 12 12.5
1.3 Selection guide for DHW heating
Standby instantaneous water heater
This makes DHW at drawing temperature
instantly available from the Vitodens.
The adjacent diagram illustrates the
changes in outlet temperature, subject to
the volume flow at the tap.
The DHW volume drawn is limited by a
throughput limiter to 8 litres/minute D.
If a greater volume of water is required
A
cold water needs to be admixed, which
reduces the outlet temperature.
The illustration of the outlet temperature
characteristics is based on a cold water
inlet temperature of 10 ºC.
A DHW outlet temperature at Vitodens
B Mixing range
C DHW outlet temperature at the
mixer tap
D Throughput limitation
13 13.5 14
300
1
1.0
0.7
½"
10
6.6 26.0
24
590
3 8
10 57
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