Viessmann VITODENS 050-W Technical Manual page 46

Design information
Cold water installation of Vitodens 050-W gas condensing combi boiler
GH L K M
A Visible drain pipe outlet point
B Safety valve
Shock arrestors
Ø 86
5
R½"
DHW circulation
DHW circulation pipes increase DHW convenience and reduce water
consumption. These benefits 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 pipe length of 7 m upwards, we recommend the installation
of a DHW circulation pipe with appropriate thermal insulation in
accordance with the Energy Saving Ordinance [Germany]. The
Energy Saving Ordinance specifies that the DHW circulation pipe
should include a circulation pump, check valve and time switch for
stopping DHW circulation during the night.
Power supply for DHW circulation pump
DHW circulation pumps equipped with their own internal control unit
must be connected via a separate power supply. Connecting the
power supply via the heat generator control unit or its accessories is
not permissible.
VIESMANN
46
(cont.)
B
C D E F
A
Safety assembly
D
C Non-return valve
D Drain
E Shut-off valve
F Cold water
G Heating flow
H DHW
K Gas connection
L Cold water
M Heating return
A safety valve to DIN 1988 is only required if the mains water supply
pressure exceeds 10 bar (1 MPa) and no DHW pressure reducing
valve is installed (to DIN 4753).
AT: A safety valve to DIN 1988 is only required if the mains water
supply pressure exceeds 6 bar (0.6 MPa) and no DHW pressure
reducing valve is installed (to DIN 4753).
Install a safety valve if the cold water inlet is equipped with a non-
return valve. In addition remove the toggle from the cold water shut-
off valve.
Non-return valves are commonly found in pressure reducers and
combined shut-off and non-return valves.
If the pipework to which the Vitodens is connected also supplies
draw-off points at which water hammer may occur (e.g. pressure
washers, washing machines or dishwashers): Install shock arrestors
near the source of the water hammer (recommended).
Flexofit S made by Flamco-Flexcon
or
Reflex made by Winkelmann + Pannhoff GmbH (available from your
local dealer).
Safety valve
The safety valve must be installed.
We recommend you install the safety valve higher than 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.
Drinking water filter
Install a drinking water filter to DIN 1988-200.
Using a non-return valve
If using a DHW cylinder adjacent to the boiler, we recommend instal-
ling a non-return valve in the heating water connection line to pre-
vent the DHW cylinder cooling due to any recirculation that may
occur.
VITODENS