Rheem Water Heater - Manual (Page 77)

WATER SUPPLIES
77
a scaling water supply calcium carbonate is deposited out of the water onto
etallic surface. Where the saturation index exceeds +0.40, the water
ATER HEATERS NOT INSTALLED IN ACCORDANCE WITH THE ABOVE
ILL NOT BE COVERED BY THE WARRANTY.
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 a corrosion resistant heating unit should be used.
In
any hot m
is scaling and an expansion control valve* must be fitted on the cold water line
after the non-return valve. Where the saturation index exceeds +0.80, a low
watts density heating unit should be used.
* Refer to the
cold water connection detail on page 36.
W
ADVICE W