Viessmann VITODENS 200-W Technical Manual page 36

Design information
■ Generally install a low loss header with the Vitodens 200-W in multi-
boiler systems.
■ When balancing the low loss header, adjust the flow rate on the
equipment side approx. 10 to 30 % lower than the flow rate on the
system side (reducing the return temperature).
■ The low loss header should be sized for the max. volume flow that
may occur in the overall system.
The low loss header separates the heat source (boiler circuit) from the
downstream heating circuits.
Install a low loss header if the maximum flow rate of an individual
design is greater than the values shown in the table below.
Boiler
Vitodens 200-W, 17 - 45 kW
Vitodens 200-W, 17 - 60 kW
Vitodens 200-W, 30 - 80 kW
Vitodens 200-W, 30 - 105 kW
We recommend installing a low loss header if the minimum flow rates
listed in the table below cannot be guaranteed.
Boiler
Vitodens 200-W, 17 - 45 kW
Vitodens 200-W, 17 - 60 kW
Vitodens 200-W, 30 - 80 kW
Vitodens 200-W, 30 - 105 kW
4
For installation designs in conjunction with low loss headers, see the
relevant sample application in the "System examples" document.
Boiler circuit
The circulation pump in the Vitodens must be able to supply the
required water volume against the (mostly low) pressure drop of the
boiler circuit; the pressure drop of the low loss header is negligible.
Subject to the water volume circulating in the generator circuit, the
respective residual head may be determined for sizing the internal pipe
diameters using the pump diagram; alternatively the variable speed
pump can be adjusted accordingly.
Heating circuit
The central heating pumps to be installed on site must be able to
deliver the water volume in the heating circuits against their pressure
drop; size the pumps accordingly.
Principle of operation
T1
V primary
V secondary
T2
V Heating water volume in the heat source circuit (approx.
primary
10 - 30 % less than V
V Heating water volume heating circuit
secondary
T Flow temperature boiler circuit
1
VIESMANN
36
(cont.)
Max. flow rate
l/h
3500
3500
5700
5700
Min. flow rate
l/h
450
450
1300
1300
T3
T4
)
secondary
T Return temperature boiler circuit
2
T Heating circuit flow temperature
3
T Heating circuit return temperature
4
Q Amount of heat supplied by the boiler
primary
Q Amount of heat transferred by the heating circuit
secondary
V < V
primary secondary
T > T
1 3
≃ T
T
2
4
Q = Q
primary secondary
Note
Suitable thermometers in the flow and return of the low loss header
make adjustments easier.
Low loss header in conjunction with Divicon heating circuit dis-
tributor
For description and specification, see page 14.
Low loss header for the Vitodens 200-W with 45 and 60 kW from
the Vitoset range
See the "Vitoset" pricelist.
KV
HV
KR
HR
HR Heating return
HV Heating flow
KR Boiler return
KV Boiler flow
Flow rate 4
m 3 /h
max.
Connections
- Female thread Rp 1
- Male thread R
- Flange DN
Dimen a mm 500
sions
b mm 360
c mm 270
d mm 80
e mm 50
Low loss header for the Vitodens 200-W with 80 and 105 kW
See page 23.
Low loss header with distributor/manifold for multi-boiler sys-
tems with 2 to 4 Vitodens 200-W
For description and specification, see page 28.
4 8 10 18
1¼ 2
65 80
500 800 1400 1450
360 650 1000 1000
270 550 1000 1000
80 120 160 200
50 80 80 120
VITODENS 200-W