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. A corrosion resistant heating unit must be used for the Rheem warranty to apply to
the heating unit. 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 e0.40, 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 standard watts density
heating unit. A low watts density heating unit must be used for the Rheem warranty to apply to the heating
unit.
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
37 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
SUMMARY OF WATER CHEMISTRY ADVICE AFFECTING WARRANTY
The water heater and its components are not suitable for certain water chemistries. Those chemistries are
listed below. If the water heater is connected at any time to a water supply with the following water chemistry,
the Rheem warranty will not cover any resultant faults on the components listed below:
Water Chemistry
Component
Chloride > 250 mg/L
water heater cylinder and heat exchanger
pH < 6.0
water heater cylinder and heat exchanger
Saturation Index (SI) < -1.0
copper sheathed heating unit
Saturation Index (SI) > +0.4
(if an expansion control valve is not fitted)
water heater cylinder and heat exchanger
temperature pressure relief valve
Saturation Index (SI) > +0.8
standard watts density heating unit
