WATER SUPPLIES
20
SATURATION INDEX
The saturation index (SI) is used as a measure of the water’s corrosive or scaling
properties. The saturation index figures stated are calculated using a water
temperature of 80°C.
In a corrosive water supply, the water can attack copper parts and cause them
to fail.
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 very scaling. An
expansion control valve must be fitted on the cold water line after the non-return
valve to protect and for the Rheem warranty to apply to the temperature pressure
relief valve and water heater cylinder.
Where the saturation index e0.80, the Rheem warranty does not apply
to a stainless steel cylinder.
Water which is scaling may be treated with a water softening device to reduce
the saturation index of the water.
Refer to the Saturation Index chart on page 20.
Refer to the cold water connection diagram on page 35 for the position of the
expansion control valve.
SATURATION INDEX (SI)
GAS STORAGE WATER HEATERS - STAINLESS STEEL
corrosive
-1.0
WITHIN WARRANTY
SPECIFICATION
SATURATION INDEX
(calculated @ 80°C water temperature)
very corrosive
very scaling
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