Safety Valve; Connecting The Dhw Circulation Pipe For Cylinder Banks - Viessmann VITOCELL 300-V VIB-A+ Installation And Service Instructions Manual

Installation sequence
Connections on the DHW side
D
F
G
E
C
A
B
Fig. 15 Example: 300 l capacity
Diaphragm expansion vessel
A
Drain
B
DHW circulation pipe
C
DHW
D
Spring-loaded check valve
E
DHW circulation pump
F
Visible discharge pipe outlet point
G
H

Safety valve

Shut-off valve
K
Safety valve
The system must be equipped with a type-tested dia-
phragm safety valve as protection against overpres-
sure.
Permissible operating pressure: 10 bar (1 MPa).
The connection diameter of the safety valve must be
as follows:
For 160 and 200 l cylinder capacity: R
■
max. heat input 75 kW
■ For 300 l to 1000 l cylinder capacity: R
max. heat input 150 kW
■ For 1000 l to 5000 l cylinder capacity: R 1 (DN 25),
max. heat input 250 kW
Select a safety valve with a higher rating if the heat
input of the DHW cylinder is greater than the maximum
heat input assigned to the capacity. (See DIN 4753-1,
issue 3/88, section 6.3.1).
Install the safety valve in the cold water line. Ensure it
cannot be shut off from the DHW cylinder. There must
be no constrictions in the pipework between the safety
valve and the DHW cylinder.

Connecting the DHW circulation pipe for cylinder banks

Note
Always install cylinder banks with connected DHW cir-
culation.
18
(cont.)
P
H
K M O K R
L N K
(DN 15),
½
(DN 20),
¾
K P
O S T
Flow regulating valve
L
Pressure gauge connector
M
Non-return valve
N
Drain
O
Cold water
P
Drinking water filter
R
S Pressure reducer
Non-return valve/pipe separator
T
!
Please note
Never seal off the safety valve discharge pipe.
The overpressure can damage the system.
Ensure that any expelled water is safely and
visibly drained into a drainage system.
Position a sign close to the safety valve dis-
charge pipe, or ideally on the safety valve itself,
with the following inscription: "For safety rea-
sons, water may be discharged from the dis-
charge pipe during heating! Never seal."
Install the safety valve above the top edge of the DHW
cylinder.