Baxi Potterton Solar manual Maintenance, Cylinder, Refer to manufacturers documentation

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.

Solar fluid concentrations

% volume	Density at20°C g/cu.cm	RefractiveIndexnD20	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

24 Potterton Solar - Solar Thermal Domestic Hot Water System