■ Mixer PCB, capable of communicating with the control unit via
PlusBus
■ Adjustable bypass
■ Flow temperature sensor
■ Connection set for surface mounting with:
– Connection pipes
– Shut-off valves for heating water flow and return, with boiler
drain & fill valve
– 2 connectors for DHW
– 2 connectors each for solar flow and return (R ¾/Ø 22 mm)
– Gas shut-off valve with thermally activated safety shut-off valve
■ Balanced flue extension, boiler flue connection
■ Cover with same design as the boiler
Note
In combination with the assembly kit, the Vitodens 242-F has protec-
tion class IP X1.
8.2 Decision making aids for DHW heating
To provide the perfect solution for every situation, the Vitodens is
available in the following versions:
■ Vitodens 200-W
– As a gas system boiler in combination with a separate DHW cyl-
inder
– As a gas condensing combi boiler with integral, direct DHW
heating
■ Vitodens 222-W
With integral DHW loading cylinder
■ Vitodens 222-F and 242-F
With integral DHW loading cylinder
Various factors should be taken into consideration when designing
heating systems and deciding between a gas system boiler with a
separate DHW cylinder or a gas system boiler with an integral DHW
loading cylinder:
■ DHW demand, convenience
■ Use of the various connected draw-off points
■ Distance of the draw-off points from the boiler
■ System modernisation
■ Space available
■ Water quality
Information on water quality
During DHW heating, settling of lime on the surfaces of the plate
heat exchanger cannot be completely prevented. The tendency
towards limescale build-up depends on various conditions, predomi-
nantly on the substances contained in the water, the amount of water
that is heated (DHW consumption) and the DHW temperature.
Although scale deposits inside the plate heat exchanger are gener-
ally minor enough not to cause any reduction in DHW output, such
impairment cannot be excluded with increased water hardness.
From a water hardness of 20 °dH (3.5 mol/m
3
) and higher, we there-
fore recommend the use of DHW cylinders with internal indirect coils
or a water treatment system in the cold water supply when heating
DHW.
Please note that regional water supply utilities frequently specify an
average water hardness. Higher levels of water hardness may there-
fore occur from time to time. This may make the use of a water treat-
ment facility advisable even from 17 °dH (> 3.0 mol/m
3
) upwards.
Selection table
Vitodens 200-W
gas condensing
system boiler
with separate
DHW cylinder
Vitodens 222-W
with integral
DHW loading
cylinder
Vitodens 222-F
with integral
DHW loading
cylinder
Vitodens 242-F
with integral, du-
al mode DHW
loading cylinder
DHW de-
mand, con-
venience
DHW demand for an apartment
+
+
+
+
DHW demand for a detached house
+
+
+
+
Centralised DHW demand for an apartment
building
+
–
–
+
Decentralised DHW demand for an apartment
building
+
0
0
–
Use of the
various
connected
draw-off
points
One draw-off point
0
0
0
0
Several draw-off points, not used simultane-
ously
+
+
+
+
Several draw-off points, used simultaneously
+
+
+
–
Distance of
draw-off
point from
boiler
Up to 7 m (without DHW circulation pipe)
+
+
–
–
With DHW circulation pipe
+
–
+
+
Modernisa-
tion
DHW cylinder installed
+
–
–
–
Replacement of an existing combi boiler
–
0
0
–
Space
available
Minimal space available (siting in a recess)
0
0
0
0
Sufficient space available (installation room)
+
+
+
+
Design information
(cont.)
VITODENS
VIESMANN
125
5853906
8
Содержание Vitodens 200-W B2HE
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