Viessmann vitodens Technical Manual page 30

1.3 Selection guide for DHW cylinders
Instantaneous water heater
200
Instantaneous water heater (Vitodens 200, gas fired combination boiler)
An electronically regulated plate heat
exchanger is integrated into the
Vitodens 200.
Plate heat exchanger specification
1
Capacity
Connections
Hot and cold water
Max. operating pressure
Output
Rated output range of the
gas fired combination boiler
Continuous DHW output
for DHW temperature rise
from 10 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
Volume flow at the tap (mixed water volume) in l/min
30
This makes DHW at drawing temperature
instantly available from Vitodens for
approx. 45 s.
litres
G (male thread)
bar
kW
kW
l/h
litres/minute
ºC
B
8 8.5 9 9.5 10 10.5 11 11.5
A
12 12.5 13 13.5 14
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
flow rate limiter to 8 litres/minute D.
If a greater volume of water is required,
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
D Throughput limitation
VITODENS
0.2
½"
10
8.8 26.0
24
590
3 8
10 57