Vaillant Solar System and auroSTOR unvented solar..., Start-Up, Maintenance And Troubleshooting Manual

Page: 30 / 69

37 Manual - Solar hot water systems 0020009607_02
thermostat mixer
mixed water
cold water
warm water
Fig. 5.14 Hot water thermostatic mixing valve
2 4
6
2
3
1
5
Fig. 5.15 Installation of the hot water thermostatic mixing valve
(for systems without secondary return)
Key
1 Hot water pipe
2 check
valve
3 Cold mains water supply pipe
4 Hot water thermostatic mixing valve
5 Expansion relief valve
6 Bivalenter solar cylinder
5.6 Installation of the cold water supply pipework
5.6.1 Mains water supply pressure
The performance of unvented cylinders depends on the
available mains water pressure and the flow rate.
In order for the performance of the auroSTOR solar
cylinder to be ideal, an appropriate cold water supply
must be available, i. e. the measured static pressure
must be at least 2.0 bar. A corresponding flow rate of at
least 20 - 25 l/min should be available.
h Note!
The mains water pressure is reduced during
periods of high water consumption.Make sure
you take measurements during these periods of
time.
Example:
The available flow rate of mixed water of 40 °C is 25 l/
min (15 l/min hot water of 60 °C from the solar cylinder
mixed with 10 l/min cold water of 10 °C) if the measured
static cold mains water pressure is 2 bar and the
available flow rate 30 l/min.
The solar cylinder operates satisfactorily at a mains
water pressure of below 2 bar, but at a reduced flow
rate.The unvented solar cylinder should not be installed
if the mains water pressure is below 1 bar.You can obtain
information on alternative hot water supply systems
from Vaillant Ltd.
To keep the friction losses at a minimum, a minimum
diameter of 22 mm is recommended for the cold water
supply in the building, satisfactory performances can
also be achieved with 15 mm pipes however.
5.6.2 Cold water piping
2
4 3
B
1
A
Fig. 5.16 Water control pack
Key
A Cold water connection
B Cylinder
connection
1 Expansion relief valve
2 Pressure limiting valve with filter
3 Connection for hot water expansion tank
4 Balanced pressure cold water connection
• Connect both parts of the water control pack as
illustrated in Fig. 5.16.
• When installing the valves, make sure they are aligned
in such a way that the 15 mm connection of the
expansion relief valve (Fig. 5.16, pos.
2 ) can be
connected to the tundish.
• Install the discharge pipe of the expansion relief valve
(Fig. 5.16, pos. 2 ) so that it has a constant outward
slope and ends at a safe, visible point where there is
no risk of freezing.
Installation 5