53
Manual - Solar hot water systems
Tube collectors auroTHERM exclusive
Flow rate
Minimum cross-section of the copper pipe in
the solar circuit at a total pipe length of:
Number in series
Net surface area
l/min
l/h
20 m
50 m
1 0.82
0.55
33
15
15
2 1.64
1.10
66
15
15
3 2.64
1.65
99
15
15
4 3.28
2.20
132
15
22
5 4.10
2.75
165
15
22
Pump speed:
Minimum (speed 1)
Maximum (speed 3)
Table 6.1 Layout of the pipe cross-section and pump speed
depending on the collector connection for tube
collectors
Flat collectors VFK 900
Flow rate
Minimum cross-section of the copper pipe in
the solar circuit at a total pipe length of:
Number
in series
l/min
l/h
20 m
50 m
1 1
1.33
80
15
15
2 2
2.66
160
15
15
3 3
4.00
240
15
15
4 4
5.33
320
15
18
Pump speed:
Minimum (speed 1)
Maximum (speed 3)
Table 6.2 Layout of the pipe cross-section and pump speed
depending on the collector connection for flat
collectors
The pump speed is used to achieve a particular flow rate
in the collector array. The final flow rate should not be
significantly above or below the calculated value.
An up
to 10 % lower solar gain or unnecessarily high power
consumption of the pump can otherwise be the
consequence.
Make the pump setting as follows:
Let the pump run first at the lowest speed (minimum
power consumption).
Check whether the calculated value is achieved on the
flow rate meter.
Example:
The installed (net) collector surface area for 3 VTK550
is 2.64 m
2
.
Multiplied with the value for the specific flow
rate of 0.66 l/m
2
• min, it results in a calculated flow rate
of 1.6 l/min, which should be indicated by the flow rate
meter (see Fig. 6.2).
For the design and function of the flow rate meter, refer
to Section 4.5, Flow rate meter.
Select the next pump speed if the calculated flow rate is
not achieved on the flow rate meter. Switch to a lower
speed if it is exceeded. If the flow rate is unable to be
achieved even at the highest pump speed, check
whether it is possible to switch fewer collectors in series
and resort to a combination of series and parallel
connections.
Also check other ways of reducing the pressure loss.
Observe here the Vaillant solar planning information.
6.3
Programming the flow rate on the controller
When programming the flow rate on the solar control,
refer to Section 6.1, Setting system parameters, of the
auroMATIC 560 operating and installation manual.
6.4
Filling the hot water secondary circuit
a
Caution!
Risk of damage!
Do not manually open the temperature/pressure
relief valve or the expansion vessel for venting
purposes. Any foreign matter in the pipework
may cause damage to the valve seats.
• Make sure the cylinder drain valve (
11
, Fig. 5.1) is
closed.
• Open all cold and hot water taps and the
corresponding outlets.
• Open the mains water supply to the auroSTOR and fill
it with water until it flows freely out of the outlets.
Make sure all air bubbles have been removed.
• Close the outlets and check the system for leaks.
Check in particular the immersion heater connection
for leaks.
The system must now be flushed thoroughly.
• Open the hot water taps at the opposite ends of the
systems and let the water flow out for at least 5
minutes.
• Close the hot water taps.
Start-up 6
