Safety Valve - Viessmann Vitocell 100-U Installation Instructions For Contractors

Connections on the DHW side

Safety valve

G
Shut-off valve
H
Flow regulating valve
K
(installation recommended)
Pressure gauge connection
L
Non-return valve
M
Drain outlet
N
Cold water
O
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 safety valve must have the following connection
diameter:
R (DN 15), max. heat input 75 kW
½
If the heat input of the DHW cylinder exceeds 75 kW,
select an appropriately rated safety valve for the heat
input (see E-DIN 1988-200).
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.
18
(cont.)
Drinking water filter
P
Pressure reducer to DIN 1988-2, Dec. 1988 issue
R
Non-return valve/pipe separator
S
Upper indirect coil, designed for connection to a
T
boiler
Expansion vessel, suitable for drinking water
U
(option)
Temperature sensor, high limit safety cut-out (STB)
V
Never seal off the safety valve discharge pipe. Ensure
that any expelled water is safely and visibly drained
into a drainage system. Position a sign close to the
safety valve discharge pipe, or ideally on the safety
valve itself, with the following inscription: "For safety
reasons, water may be discharged from the discharge
pipe during heating. Never seal."
Install the safety valve above the top edge of the DHW
cylinder.