Rheem 511161 Owner's Manual And Installation Instructions page 16

WATER SUPPLIES
ANODE INSPECTION AND REPLACEMENT
The anode installed in this water heater will slowly dissipate whilst protecting the cylinder. The life of the
cylinder may be extended by replacing the anode.
For water supplies which are either softened or desalinated, or where the water supply may alternate between
a water tank and a reticulated public supply or another supply, or where there is a variable supply (e.g. from a
bore or public reticulated supply from various water sources), the anode must be inspected (and replaced if
there is any sign of depletion) within five (5) years of its installation.
For all water supplies, if the anode is not replaced during a major service (refer to
Years"
on page 12) then the maximum time after installation when the anode should be replaced for this water
heater is eight (8) years.
CAUTION
If the water supply has a TDS greater than 150 mg/L and a green anode has not been changed to a black
anode, or if the TDS is greater than 600 mg/L and the anode has not been changed to a blue anode, there is
the possibility the anode may become overactive and hydrogen gas could accumulate in the top of the water
heater during long periods of no use.
If, under these conditions, the water heater has not been used for two or more weeks the following procedure
should be carried out before using any electrical appliances (automatic washing machines and dishwashers)
which are connected to the hot water supply.
The hydrogen, which is highly flammable, should be vented safely by opening a hot tap and allowing the water
to flow. There should be no smoking or naked flame near the tap whilst it is turned on. Any hydrogen gas will
be dissipated. This is indicated by an unusual spurting of the water from the tap. Once the water runs freely,
any hydrogen in the system will have been released.
SATURATION INDEX
The saturation index 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.
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 to a solar collector in an open circuit solar water heater system. A
corrosion resistant heating unit must be used for the Rheem warranty to apply to the 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 an open circuit solar water
heater system should be covered when the water heater is not intended to be used for more than four (4)
weeks.
Where the saturation index exceeds +0.80, the Rheem warranty does not apply to a standard watts density
heating unit or to a solar collector in an open circuit solar water heater system. 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
Contact Rheem Service or their nearest Accredited Service Agent if a replacement heating unit is required.
Refer to the cold water connection detail on page
on page 17.
43 for the position of the expansion control valve.
16
"Major Service Every Five