WATER SUPPLIES
18
ANODE INSPECTION AND REPLACEMENT
The anodes installed in this water heater will slowly dissipate whilst protecting the cylinder. The life of the
cylinder may be extended by replacing the anodes.
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), each 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 anodes are not replaced during a major service (refer to
on page 16) then the maximum time after its installation when the anodes 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 an 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 heat exchanger in a continuous flow water heater.
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 copper heat exchanger
in a continuous flow gas booster water heater.
Water which is scaling may be treated with a water softening device to reduce the saturation index of the water.
Refer to the
on page 19.
cold water connection detail on page
45 for the position of the expansion control valve.
