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A self-priming pump with a pressure of 2 to 3 bar is
required to fill the solar circuit. This is how to do it (see
Fig. 6.1):
• After flushing close the fill/drain valve (12) and pump
in solar fluid once a pressure of 1.7 bar is achieved.
• Close the fill/vent valve (1) too and place the three-
way ball valve (15) into circulation position.
• Switch off the filling pump and switch on the solar
pump (13) to allow air bubbles to escape via the
bleeder.
• Block the gravity brakes (8 and 14) (position 45°) to
discharge the remaining air.
• When bleeding is completed release the gravity brakes.
Collector circuit filling pressure
The filling pressure Pa should be approx. 0.5 bar over
the static pressure Pstat.
Pa = h x 0.1 + 0.5 bar
6.2
Setting the flow rate and pump
2
Fig. 6.2 Setting the flow rate
The 3-speed circulating pump can be fine-tuned to
adjust the flow rate to the collector's performance.
h
Note!
We recommend the following values
for flat collectors:
for vacuum tube collectors:
of collector surface.
Manual - Solar hot water systems 0020009607_02
1,1 l/min
0,66l/min per m
0,4l/min per m
This is how to do it:
• Use Table 6.1 to calculate the volume flow to be set by
multiplying the installed collector surface by the value
2
0.66 l/m
•min (flat collectors) or 0.40 l/m
collectors).
• Set the pump speed to roughly set the flow rate.
• Use an Allen key to finely adjust the flow rate at the
adjustment valve (see Fig. 6.2 Pos. 1).
The adjusted flow rate can be viewed on the display (2).
Table 6.1 and 6.2 provide reference values for possible
pump speeds depending on the collector connection and
pipe length and cross-section.
If you use auroMATIC 560 solar control, the flow rate
can be used to calculate the gain. To make an accurate
calculation, the flow rate must be entered on the
controller. You can find further information in the
operating and installation manual of the control.
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:
1
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 for tube collectors:
The installed (net) collector surface area for 3 VTK 570
units is 3.0 m
flow value of 0.4 l/m
flow rate of 1.2 l/min. This should be displayed at 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.
2
Select the next pump speed if the calculated flow rate is
2
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.
2
. When multiplied by the specific volume
2
•min, this produces a calculated
Start-up 6
2
•min (tube
57
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