Setting The Flow Rate - Bosch AGS10-2 Installation And Servicing Instructions

6.2.6 Determining the frost threshold temperature
To determine the degree of frost protection, we recommend checking
the frost protection of the heat transfer fluid when first putting the
system into operation, by means of a frost protection gauge (a
refractometer). This check should be repeated at regular intervals (at
least every two years).
The commonly used instruments for testing motor vehicle engine
coolants are not suitable for this purpose. A suitable device can be
ordered separately.
For system operation with heat transfer medium LS
If the solar system is operated with heat transfer medium LS, the value
must be converted using Tab. 10.
Value recorded for heat transfer
medium L (concentration)
– 23 °C (39 %)
– 20 °C (36 %)
– 18 °C (34 %)
– 16 °C (31 %)
– 14 °C (29 %)
– 11 °C (24 %)
– 10 °C (23 %)
– 8 °C (19 %)
– 6 °C (15 %)
– 5 °C (13 %)
– 3 °C (8 %)
Table 10
6.2.7 Correcting frost protection
NOTICE: Frost damage
▶ Every two years, check whether the required frost
protection level (to at least –25 °C) is being
maintained.
If the minimum frost protection level is not being maintained, more heat
transfer fluid must be added.
▶ Use Tab. 11 to determine the volume of the system, so that you can
calculate the exact amount to be added (which is equal to the amount
which first needs to be drained out).
System part
Collector: see collector instructions (technical data)
1 single-line solar pump station
1 twin-line solar pump station
1 coil in the solar cylinder (see technical guide)
1 m Cu pipe Ø 15 mm
1 m Cu pipe Ø 22 mm
1 m Cu pipe Ø 28 mm
1 m Cu pipe Ø 35 mm
1 m Cu pipe Ø 42 mm
1 m stainless steel corrugated pipe DN16
1 m stainless steel corrugated pipe DN20
1 m stainless steel corrugated pipe DN25
Table 11 Volume of the separate system parts
AGS10-2, AGS10E-2, AGS20-2, AGS50-2
Corresponds to frost protection
with heat transfer medium LS
– 28 °C
– 25 °C
– 23 °C
– 21 °C
– 19 °C
– 16 °C
– 15 °C
– 13 °C
– 11 °C
– 10 °C
– 8 °C
Fill volume
0.20 l
0.50 l
0.13 l
0.31 l
0.53 l
0.86 l
1.26 l
0.26 l
0.41 l
0.61 l
▶ Use the formula on the right to determine the amount of concentrate
to be added (V ).
replace
V = V x
replace total
Table 12 Formula for calculating the amount of fluid to be replaced
Example of heat transfer medium L:
• System volume (V ) = 22 l
total
• Frost protection level (reading taken): – 14 °C
• Equals concentration of ( Tab. 10, page 15): 29 % (C = 29)
• Result: V = 4.3 l
replace
▶ Drain the calculated amount to be added (V
concentrate.
6.3

Setting the flow rate

The flow rate is set when the system is cold (30 - 40 °C).
• When the solar pump is speed-controlled, the controller determines
the flow rate based on operating requirements.
• If the controller is not equipped with speed control or if speed control
has been deactivated, the flow rate must be set to a fixed flow rate.
If you wish to set the flow rate:
1. Carry out the preparatory work ( Chapter 6.3.1)
2. Check the flow rate ( Chapter 6.3.2)
3. Set the flow rate ( Chapter 6.3.3)
6.3.1 Carrying out the preparatory work
▶ Rotate ball valves [1] to 0° (check valves ready for operation).
▶ Completely open the flow limiter [2].
▶ On the controller, select mode "Manual ON" ( controller instruction
manual).
1
60 60
40 °C 80 40 °C 80
100 100
20 20
0 120 0 120
2
3
Fig. 26
[1] Gravity brake ready for operation
[2] Adjusting screw on the flow limiter, depending on the type
[3] Read-off edge for the flow rate, depending on the type
Commissioning | 15
43 - C
concentration
100 - C
concentration
) and add
replace
S
3
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