16
Installation and maintenance instructions for uniSTOR 0020111105_00
5.2
Installing hot water pipes
>
Connect the hot water piping to the 22 mm hot water
draw off of the cylinder.
>
Lay the 22 mm piping up to the first T-piece.
The required diameter of subsequent pipes depends
on the system design.
Installing the circulation line
1
5
8
1
4
3
7
2
6
Fig. 5.2 Installing the circulation line
Key
1 Non-return
valve
2 Hot water pipe
3 Circulation
line
4 Circulation pump
5 Contact
thermostat
6 Expansion relief valve
7 Cold mains inlet
8 Domestic hot water cylinder
Where possible, avoid installing a circulation line, since
a circulation line results in higher energy consumption.
i
If you are not using the secondary return,
this must be properly closed off with the
cap
included in delivery.
i
If you are installing a circulation line, an addi-
tional expansion vessel may be required in
certain circumstances.
If the installation of a circulation line is required, keep
circulation operations to a minimum by only using circu-
lation mode when required for demand and temperature
reasons.
The cylinder has a connection with a 15 mm diameter
for a second circulation line.
>
Connect a WRAS-approved circulation pump (
4
)
with a non-return valve to the secondary return.
>
Connect the circulation line (
3
) to the hot water pipe (
2
).
5.3
Installation of cold mains inlet
5.3.1
Pressure in cold mains inlet
The efficiency of an unvented cylinder depends on the
available pressure in the cold mains inlet and the flow
rate. To obtain optimum cylinder output, there must be
a suitable cold mains inlet, i.e. the measured static line
pressure must be at least 2.0 bar. A corresponding flow
rate of at least 20-25 l/min must be available.
i
The pressure in the cold mains inlet will be
reduced at times of high consumption. Thus,
measurements should be taken at such times.
The cylinder still works satisfactorily with a pressure
below 2 bar but the flow rate is reduced. If the pressure
is below 1 bar, you should not install an unvented cylin-
der. Vaillant Ltd. can provide information on alternative
hot water supply systems.
80
4
5
60
3
40
2
Inlet pressure (bar)
Flo
w r
at
e (l/
min
)
20
1
0
Fig. 5.3 Maximum flow rate of the cold water assembly based
on the supply pressure
The displayed flow rates apply to installations in which
the cold water supply has a dynamic pressure and flow
rate appropriate for the system.
If the static water pressure is less than 1 bar, contact
Vaillant Ltd.
5 Installation
