Baxi Potterton Solar - Manual (Page 24)

Potterton Solar - Solar Thermal Domestic Hot Water System 24
4.0 Maintenance
4.1 Check heat transfer fluid
The heat transfer fluid must be checked every two years
with regard to its antifreeze and pH value.
- Check antifreeze using antifreeze tester.Target value is
approximately -21 deg C (40% concentration).
Do not allow to fall below 30% concentration.
If necessary replace or replenish the solar heat
transfer fluid.
- Check pH value with a pH indicator rod (target value
approx. pH 7.5). If the limit pH value is less than pH 7,
replace the heat transfer fluid.
4.2 Maintenance of the collector
The collector or the collector array must be inspected
visually, once a year, for any damage, leaks and
contamination.
4.3 Cylinder
Refer to manufacturers documentation.
% volume Density at 20°C g/cu.cm Refractive Index nD20 Frost protection °C
25 1.023 1.3627 -10
30 1.029 1.3690 -14
35 1.033 1.3747 -17
40 1.037 1.3801 -21
45 1.042 1.3855 -26
50 1.045 1.3910 -32
Solar fluid concentrations