Viessmann Vitodens 200 WB2 Series Technical Data Manual page 35

Accessories for Vitodens 200
The temperature sensor connection [TS]
typically located at the top of the low-loss
header ensures low return temperatures to
the Vitodens 200 boiler at all times,
increasing operational efficiency.
In addition, the low-loss header helps
eliminate air and debris [D] from the heating
system.
See figures on the right for an illustration of
the principle of operation.
The low-loss header is available in the
following sizes. Select the size based on the
maximum system flow rate of your
application.
Model No. Max. system flow rate
Type 80/50 17.6 GPM / 4 m
Type 120/80 35.2 GPM / 8 m
*1
Type 160/80 44 GPM / 10 m
Type *1 80 GPM / 18 m
200/120
*1
Product does not look exactly as
illustrated.
(continued)
BS
TS
BY
3
/h
3
/h
3
/h
3
/h
BR
Low-loss header design
(Type 80/50 or 120/80)
T1
V
primary
T2
Principle of Operation
SC
AB
SW
SS
SR
D
DV
T3
V T4 V
bypass secondary
T4
Vitodens 200 Accessories
Legend
AB Air Bleed
BR Boiler Return
BS Boiler Supply
BY Bypass (with laminar flow)
D Debris and/or air
DV Drain Valve
SC Sensor Cable
SR System Return
SS System Supply
TS Viessmann Temperature Sensor
SW Sensor Well
IMPORTANT
Use only a Viessmann supplied temperature
sensor. Do not use any other
manufacturer's temperature sensor.
T1 Boiler supply temperature
T2 Boiler return temperature
T3 System supply temperature
T4 System return temperature
V Boiler circuit flow rate
primary
V Heating circuit flow rate
secondary
V Bypass flow rate
bypass
Q Heat supplied by boiler
primary
Q Heat consumed by system
secondary
V < V
primary secondary
T1 > T3
T2 = T4
Q = Q
primary secondary
T1 ± 167°F / 75°C
V =V V
secondary primary+ bypass
IMPORTANT
When installing a low-loss header, system
mixed supply temperature (T3) must be
calculated as follows:
T1 × V +T4 V
primary bypass
T3=
V
secondary
35