WATER SUPPLIES
14
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 very corrosive and the Rheem warranty does not apply to a copper
sheathed heating unit or a solar collector in a direct solar water heater system. A corrosion resistant heating
and an indirect solar water heater must be used unit must be used for the Rheem warranty to apply to the
heating unit and solar collector. This water heater is supplied fitted with a corrosion resistant heating unit.
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. Solar collectors in a direct solar water heater
system should be covered when the water heater is not intended to be used for more than two weeks.
Where the saturation index e0.80, the Rheem warranty does not apply to a standard watts density
heating unit or a solar collector in a direct solar water heater system. A low watts density heating unit or an
indirect solar water heater must be used for the Rheem warranty to apply to the heating unit or solar
collector.
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 14. Refer to the
cold water connection detail on page
48 for the
position of the expansion control valve.
Contact Rheem Service or their nearest Accredited Service Agent if a replacement heating unit is required.
-1.0
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SATURATION INDEX (SI)
SOLAR WATER HEATERS - ELECTRIC BOOST
WITHIN WARRANTY
SPECIFICATION
SATURATION INDEX
(calculated @ 80°C water temperature)
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+0.4
+0.8
0
very corrosive
very scaling
scaling
corrosive