29
Preparing the connections on the DHW side
For connecting the DHW side, observe DIN 1988 and
DIN 4753 (CH: SVGW regulations).
N
O
M
L
H
K
P
O
K
R S K N P
K
C
B
A
G
D
E
F
Fig. 25
A
Expansion vessel, suitable for drinking water
B
Visible discharge pipe outlet point (tundish)
C
Safety valve
D
DHW circulation pump
E
Spring-loaded check valve
F
Automatic thermostatic mixing valve
G
DHW
H
Heat pump terminal area (plan view)
K
Shut-off valve
L
Flow regulating valve
M
Pressure gauge connection
N
Non-return valve/pipe separator
O
Drain valve
P
Cold water
R
Drinking water filter
S
Pressure reducer
Safety valve
The DHW cylinder
must
have a safety valve to protect
against unduly high pressure.
Recommendation: Install safety valve above top edge
of cylinder. This means the DHW cylinder will not need
to be drained when working on the safety valve.
CH
: According to W3 "Principles for creating potable
water installations", safety valves must be drained
directly via a visible unrestricted drain or via a short
outlet line to the drain network.
Drinking water filter
According to DIN 1988-2, a drinking water filter must
be installed in systems with metal pipework.
Viessmann also recommends the installation of a
drinking water filter when using plastic pipes to
DIN 1988 to prevent contaminants entering the DHW
system.
Automatic thermostatic mixing valve
With appliances that heat DHW to temperatures above
60 °C, an automatic thermostatic mixing valve must be
installed in the DHW line as protection against scald-
ing.
Installation sequence
Connecting the secondary circuit
(cont.)
51
17 700 GB
Installation
