Viessmann VITODENS 200-W Technical Manual page 22

Installation accessories
Result of this example: Divicon with mixer-3 (R ¾)
Circulation pump curves and pressure drop on the heating water
side
The residual pump head results from the differential between the
selected pump curve and the pressure drop curve of the respective
heating circuit distributor or further components (pipe assembly, dis-
tributor etc.).
The following pump graphs show the pressure drop curves of the dif-
ferent Divicon heating circuit distributors.
Maximum flow rate for Divicon:
■ with R ¾ = 1.0 m 3 /h
2
■ with R 1 = 1.5 m
3 /h
■ with R 1¼ = 2.5 m 3
/h
Example:
Flow rate ´ = 0.665 m 3 /h
Selected:
■ Divicon with mixer R ¾
■ Wilo Yonos Para 25/6 circulation pump, variable differential pressure
operating mode and set to maximum delivery head
■ Pump rate 0.7 m 3
/h
Head of the relevant pump
curve:
Divicon pressure drop:
Residual head:
Note
For further components (pipe assembly, distributor, etc.) determine the
pressure drop and deduct it from the residual head.
Differential pressure-dependent heating circuit pumps
According to the [German] Energy Saving Ordinance (EnEV), circula-
tion pumps in central heating systems must be sized in accordance
with current technical rules.
Ecodesign Directive 2009/125/EC requires high efficiency circulation
pumps to be used throughout Europe from 1 January 2013, if the
pumps are not installed in the heat source.
Design information
The use of differential pressure-dependent heating circuit pumps
requires heating circuits with variable pump rates. These include, for
example, single and twin line heating systems with thermostatic valves
and underfloor heating systems with thermostatic or zone valves.
VIESMANN
22
(cont.)
48 kPa
3.5 kPa
48 kPa – 3.5 kPa = 44.5 kPa.
Wilo Yonos Para 25/6
■ Very economical HE pump (compliant with Energy Label A)
Operating mode: Constant differential pressure
700 70
600 60
500
50
400 40
300
30
200 20
100 10 B
A
0 0
0.5 1.0 1.5 2.0 2.5
0
Flow rate in m³/h
A Divicon R ¾ with mixer
B Divicon R 1 with mixer
C Divicon R ¾ and R 1 without mixer
Operating mode: Variable differential pressure
700 70
600 60
500
50
400 40
300
30
200
20
100 10
B
A
0 0
0.5 1.0 1.5 2.0 2.5
0
Flow rate in m³/h
A Divicon R ¾ with mixer
B Divicon R 1 with mixer
C Divicon R ¾ and R 1 without mixer
C
3.0 3.5
C
3.0 3.5
VITODENS 200-W