Viessmann VITODENS 242-F Technical Manual page 67

Design information
Cold water installation
B
A
C D
For connection locations, see the relevant connection set
A DHW
B DHW circulation pipe
C DHW circulation pump
D Spring-loaded check valve
E Visible discharge pipe outlet point
F Safety valve
G Shut-off valve
H Flow regulating valve
(We recommend installing and adjusting the maximum water flow
rate in accordance with the peak draw-off rate of the DHW cylinder
(see "Specification"))
Note
DHW circulation pump C and check valve D are part of the DHW
circulation pump connection set (accessories) and are fitted inside the
boiler.
Safety valve
The safety valve must be installed.
DHW circulation
DHW circulation pipes increase DHW convenience and reduce water
consumption.
These advantages result from the immediate availability of DHW at the
tap/draw-off point.
However, poor thermal insulation of the DHW circulation pipe can lead
to substantial heat losses.
From a line length of 7 m we recommend providing appropriate ther-
mal insulation for the DHW circulation in accordance with the Energy
Saving Ordinance [Germany].
VITODENS
(cont.)
F
G H KLM G
E
S
M
N
G M
K Pressure gauge connection
L Non-return valve
M Drain
N Cold water
O Drinking water filter
P Pressure reducer
R Non-return valve/pipe separator
S Diaphragm expansion vessel, suitable for DHW
We recommend installing the safety valve above the top edge of the
cylinder. This protects the valve against contamination, scaling and
high temperatures. It also means that the DHW cylinder does not need
to be drained when working on the safety valve.
This specifies that the DHW circulation pipe should, in accordance with
the Energy Saving Ordinance, include a circulation pump, a check
valve and a time switch for shutting down DHW circulation during the
night.
Only use the DHW circulation pump connection set, available as an
accessory, for installation in the boiler. The circulation pump is then
controlled by the boiler control unit.
The flow rate of the DHW circulation pump must not exceed
1.5 l/min.
Installation scheme for DHW circulation, see page 67.
O P G R N
VIESMANN
6
67