Viessmann Vitocrossal 200 CM2 Series, Technical Manual

Page: 16 / 100

Residual head
Residual head of the heating circuits
Deduct the pressure drop of the mixer and the boiler circuit (boiler,
pipework, flow distributor and return collector) from the pump head.
The total water volume of all heating circuits should be taken into con-
sideration in the boiler circuit.
Boiler circuit pressure drop
( pi flow distributor and return col heating cir-
cuit connection without mixer)
1
2
3
4
5
10
15
20
30
40
50
100
1 2 3 4 5 10 15 20
Flow rate in m³/h
Pressure drop
C B A
0.1
0.2
0.3
0.4
0.5
1
1.5
2
3
4
5
10
kPa mbar
A DN 65: Vitocrossal 300, 87 to 142 kW,
B DN 65: Vitocrossal 300, 187 and 248 kW,
C DN 80: Vitocrossal 300, 314 kW,
Mixer pressure drop
1
2
5
10
20
50
100
200
500
0.2 0.5 1 2 5 10 20
Throughput in m³/h
Pressure drop
D C B A
kPa mbar 0.1
0.2
0.5
1
2
5
10
20
50
0.1
A DN 25
B DN 32
C DN 40
D DN 50
Note
For the pressure drop of the pipe connections between the boiler and
distributor, 6 bends (90°) and 5 m pipe length are factored in. If con-
siderably different lengths and shapes are used on-site, calculate and
factor in the additional pressure drop levels.
Example for calculating the residual head
Heating system with:
– Divicon heating circuit distributor DN 80
– Heating cir-
cuit 1:
1 heating circuit connection DN 25 without mixer, heating output 35 kW,
flow rate 1.5 m
3
/h
– Heating cir-
cuit 2: 1 heating circuit connection DN 32 with mixer, heating output 60 kW,
flow rate 2.5 m
3
/h
– Heating cir-
cuit 3: 1 heating circuit connection DN 50 with mixer, heating output 150 kW,
flow rate 6.5 m
3
/h
Total flow rate 10.5 m
3
/h
Boiler circuit pressure drop
pipe conne flow distributor and return col heat-
ing circuit connection (except mixer) (see diagram) = 30 mbar
(3 kPa)
Mixer pressure drop
(see diagram)
Mixer DN 32 50
Pressure drop mbar 18 22
kPa 1.8 2.2
Sum of the boiler circuit pressure drop and heating circuit connection pressure drop
Heating circuit 1: 30 mbar (3 kPa)
Heating circuit 2: 30 mbar + 18 mbar = 48 mbar (4.8 kPa)
Installation accessories
(cont.)
16
VIESMANN
Gas condensing boilers
7
5822 449 GB