WATER SUPPLIES
57
SATURATION INDEX
The saturation index is used as a measure of the water’s corrosive or scaling
properties. In a corrosive water supply, the water can attack copper parts and
cause them to fail. Where the saturation index is less than –1.0, the water is
corrosive and warranty does not apply to a solar collector.
In a scaling water supply calcium carbonate is deposited out of the water onto
any hot metallic surface. Where the saturation index exceeds +0.40, the water
is scaling and an expansion control valve* must be fitted on the cold water line
after the non-return valve and the solar collectors should be covered when the
water heater is not intended to be used for more than two weeks. Where the
saturation index exceeds +0.80, warranty does not apply to a solar collector
unless a water softening device is installed.
* Refer to the cold water connection detail on page 40.
WATER HEATERS NOT INSTALLED IN ACCORDANCE WITH THE ABOVE
ADVICE WILL NOT BE COVERED BY THE WARRANTY.