WATER SUPPLIES
14
SATURATION INDEX
The saturation index is use
d 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 stainless steel cylinder or 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
27 for the position of the expansion control valve.
Contact Rheem Service or their nearest Accredited Service Agent if a
replacement heating unit is required.
+0.4
+0.8
0
-1.0
no
w
ar
rant
y
a
p
p
li
e
s
to
a
:
te
m
p
e
ra
tu
re
p
re
s
s
u
re
r
e
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e
f
v
a
lv
e
o
r
a
w
a
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r
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a
te
r
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n
d
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r
u
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s
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a
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p
a
n
s
io
n
c
o
n
tr
o
l
v
a
lv
e
i
s
f
it
te
d
.
no
w
ar
rant
y
a
p
p
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s
to
a
:
-c
o
p
p
e
r
s
h
e
a
th
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d
h
e
a
ti
n
g
u
n
it
SATURATION INDEX (SI)
ELECTRIC WATER HEATERS - STAINLESS STEEL
WITHIN WARRANTY
SPECIFICATION
SATURATION INDEX
(calculated @ 80°C water temperature)
no
w
ar
rant
y
a
p
p
li
e
s
to
a
:
-s
ta
n
d
a
rd
w
a
tt
s
d
e
n
s
it
y
h
e
a
ti
n
g
u
n
it
-s
ta
in
le
s
s
s
te
e
l
c
y
li
n
d
e
r
very corrosive
very scaling
scaling
corrosive
