WATER SUPPLIES
18
ANODE INSPECTION AND REPLACEMENT
The anode installed in a vitreous enamel lined steel water heater cylinder will slowly dissipate whilst
protecting the cylinder. The life of the cylinder may be extended by replacing the anode.
If the anode is not replaced during a five year service (refer to
on page 14) then
the maximum time after installation when the anode should be replaced for this water heater is 8 years.
For water supplies which are either softened, desalinated or where the water supply may alternate between
a water tank and a reticulated public supply or another supply, it is recommended the anode be replaced
within 5 years of installation.
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.
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 Solahart 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 unit must be used for the Solahart 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 Solahart 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 Solahart 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 must
be used for the Solahart 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
on page 19.
Contact your nearest Solahart Dealer if a replacement heating unit is required.
Refer to the
cold water connection detail on page
40 for the position of the expansion control valve.
