Vulcan-Hart 641 series Technical Document

This water heater must be installed and serviced by a qualified person.
Please leave this guide with the householder.
Owner’s Guide
and
Installation Instructions
Gas Domestic
Water Heater
641 series

PATENTS
This water heater may be protected by one or more patents or registered designs
in the name of Rheem Australia Pty Ltd.
TRADEMARKS
®Registered trademark of Rheem Australia Pty Ltd.
TM Trademark of Rheem Australia Pty Ltd.
Note: Every care has been taken to ensure the accuracy in preparation of this
publication. No liability can be accepted for any consequences
which may arise as a result of its application.
Warning: Upon completion of the installation and commissioning of the
water heater, leave this guide with the householder or responsible officer.
DO NOT leave this guide inside of the cover of the water heater, as it may
interfere with the safe operation of the water heater or ignite when the water
heater is turned on.

3
CONTENTS
HOUSEHOLDER –We recommend you read pages 4 to 19.
The other pages are intended for the installer
but may be of interest.
About Your Water Heater............................................................4
Regular Care ................................................................................9
Water Supplies...........................................................................13
Save A Service Call ...................................................................17
Installation..................................................................................20
Connections –Plumbing ..........................................................28
Commissioning..........................................................................32
Lighting The Water Heater........................................................33
Draining The Water Heater .......................................................36
Warranty.....................................................................................38

4
ABOUT YOUR WATER HEATER
WATER HEATER APPLICATION
This water heater is designed for use in a single family domestic dwelling for
the purpose of heating potable water. Its use in an application other than this
may shorten its life.
MODEL TYPE
The Vulcan®water heater model you have
chosen is suitable for outdoor installation only.
Water is stored in a vitreous enamel lined
steel cylinder and heated by a gas burner
located under the cylinder. The heat produced
by the burner is transferred to the water
through the base of the cylinder and through
the wall of a flue pipe which passes through
the centre of the cylinder. A flue baffle in this
flue ensures the efficiency of the water heater
is correct. The gas supply to the burner is
controlled by the thermostat so the water is
heated to a constant temperature.
Automatic safety controls are fitted to the
water heater to provide safe and efficient
operation.
HOW HOT SHOULD THE WATER BE?
The water heater features a user adjustable
thermostat, which allows you to personally
choose the most suitable temperature for your
hot water needs. Refer to “Temperature
Adjustment” on page 5.
To meet the requirements of the National
Plumbing Standard the temperature of the
stored water must not be below 60°C.
Note: AS 3498 requires that a water heater
provides the means to inhibit the growth of
Legionella bacteria in potable water. This
water heater can satisfy this AS 3498
requirement provided it is operating and the
thermostat setting is 60°C or higher, including
when it is used as an in-series booster water
heater for a solar water heater.
maximum thermostat
setting
maximum
recommended supply
temperature to
bathrooms and
ensuites
minimum
recommended stored
water temperature

ABOUT YOUR WATER HEATER
5
HOTTER WATER INCREASES THE RISK OF SCALD INJURY
This water heater can deliver water at temperatures which can cause scalding.
Check the water temperature before use, such as when entering a shower or
filling a bath or basin, to ensure it is suitable for the application and will not
cause scald injury.
We recommend and it may also be required by regulations that an approved
temperature limiting device be fitted into the hot water pipe work to the
bathroom and ensuite when this water heater is installed. This will keep the
water temperature below 50°C at the bathroom and ensuite. The risk of scald
injury will be reduced and still allow hotter water to the kitchen and laundry.
TEMPERATURE ADJUSTMENT
The temperature adjusting dial is on the
gas valve, located behind the access cover
on the lower front of the water heater. A
setting of „6‟ will normally maintain the
water temperature at about 60°C. Each
number represents a temperature
difference of approximately 6°C.
To increase the water temperature to 65°C,
turn the gas control knob anticlockwise to a
setting of „7‟. Refer to “Hotter Water
Increases the Risk of Scald Injury” on
page 5.
PIEZO IGNITION
The “Piezo” push button igniter makes
lighting the pilot flame of your water heater
very easy. Simply follow the instructions on
the label attached to the back of the access
door. There is no need for matches to light
the water heater.
PILOT IGNITER
A permanent pilot flame burns to ignite the
main burner automatically. Heat from the
pilot is absorbed by the water.

ABOUT YOUR WATER HEATER
6
WARNING
This water heater is only intended to be operated by persons who have the
experience or the knowledge and the capabilities to do so. This water heater is
not intended to be operated by persons with reduced physical, sensory or
mental capabilities i.e. the infirm, or by children. Children should be supervised
to ensure they do not interfere with the water heater.
SAFETY
This water heater is supplied with a thermostat, an over-temperature cut-out,
and a combination temperature pressure relief valve. These devices must not
be tampered with or removed. The water heater must not be operated unless
each of these devices is fitted and is in working order.
Warning: For continued safety of this water heater it must be installed,
operated and maintained in accordance with the Owner‟s Guide and Installation
Instructions.
The Vulcan warranty may not cover faults if relief valves or other safety
devices are tampered with or if the installation is not in accordance with
these instructions.
Do not store flammable or
combustible materials near the water
heater. Flammable liquids (such as
petrol), newspapers and similar articles
must be kept well away from the water
heater and the flue terminal.
Do not use aerosols, stain removers
and household chemicals near the
water heater whilst it is working. Gases
from some aerosol sprays, stain
removers and household chemicals
become corrosive when drawn into a
flame.
Do not store swimming pool chemicals, household cleaners, etc., near
the water heater.
Do not place anything on top of the water heater or in contact with the flue
terminal. Ensure the flue terminal is not obstructed in any way at any time.
Do not use Propane / Butane gas mixtures in a Propane model. A Propane
model is designed to operate on Propane only. The use of
Propane / Butane mixture, such as automotive LPG fuel, in a Propane
model is unsafe and can cause damage to the water heater.

ABOUT YOUR WATER HEATER
7
MAINS PRESSURE
The water heater is designed to operate at mains pressure by connecting
directly to the mains water supply. If the mains supply pressure in your area
exceeds that shown on page 22, a pressure limiting valve must be fitted. The
supply pressure should be greater than 350 kPa for true mains pressure
operation to be achieved.
PRECAUTIONS
Where damage to property can occur in the event of the water heater leaking,
the water heater must be installed in a safe tray. Construction, installation and
draining of a safe tray must comply with AS/NZS 3500.4 and all local codes
and regulatory authority requirements.
The water heater must be maintained in accordance with the Owner‟s Guide
and Installation Instructions. Refer to “Regular Care” on page 9 and to “Anode
Inspection and Replacement” on page 14.
If this water heater is to be used where an uninterrupted hot water supply is
necessary for your application or business you should ensure that you have
back up redundancy within the hot water system design. This should ensure
the continuity of hot water supply in the event that this water heater were to
become inoperable for any reason. We recommend you seek advice from your
plumber or specifier about your needs and building back up redundancy into
your hot water supply system.
TO TURN OFF THE WATER HEATER
If it is necessary to turn off the water heater:
Shut down the gas control (refer to “Close Down Procedure” on page 35).
Close the gas isolation valve at the inlet to the gas control.
Close the cold water isolation valve at the inlet to the water heater.
TO TURN ON THE WATER HEATER
Open the cold water isolation valve fully at the inlet to the water heater.
Open the gas isolation valve fully at the inlet to the gas control.
Light the water heater (refer to “Lighting the Water Heater” on page 33).
GOING ON HOLIDAYS
If you are going on holiday for more than a few days the thermostat can be set
to the “” (pilot) position to conserve energy (refer to point 1 of “Close Down
Procedure” on page 35). If it is necessary to turn off the water heater, refer to
“To Turn Off The Water Heater” on page 7.

ABOUT YOUR WATER HEATER
8
HOW DO I KNOW IF THE WATER HEATER IS INSTALLED CORRECTLY?
Installation requirements are shown on pages 20 to 27. The water heater must
be installed:
by a qualified person, and
in accordance with the installation instructions, and
in compliance with Standards AS/NZS 3500.4, AS 5601 or AS/NZS 5601.1,
as applicable under local regulations, and all local codes and regulatory
authority requirements.
In New Zealand, the installation must also conform with NZS 5261, as
applicable under local regulations, and the New Zealand Building Code.
VICTORIAN CUSTOMERS
Notice to Victorian Customers from the Victorian Plumbing Industry
Commission. This water heater must be installed by a licensed person as
required by the Victorian Building Act 1993.
Only a licensed person will give you a Compliance Certificate, showing that the
work complies with all the relevant Standards. Only a licensed person will have
insurance protecting their workmanship for 6 years. Make sure you use a
licensed person to install this water heater and ask for your Compliance
Certificate.
DOES THE WATER CHEMISTRY AFFECT THE WATER HEATER?
The water heater is suitable for most public water supplies, however some
water chemistries may have detrimental effects on the water heater, its
components and fittings. Refer to “Water Supplies” on page 13.
If you are in a known harsh water area or you are not sure of your water
chemistry, have your water checked against the conditions described on
pages 13 to 16.
HOW LONG WILL THE WATER HEATER LAST?
The water heater is supported by a manufacturer‟s warranty (refer to page 38).
There are a number of factors that will affect the length of service the water
heater will provide. These include but are not limited to the water chemistry, the
water pressure, the water temperature (inlet and outlet) and the water usage
pattern. Refer to “Precautions” on page 7.

9
REGULAR CARE
ANNUAL SERVICE
For safe and efficient operation, it is recommended an annual service be
conducted on the water heater.
Warning: Servicing of a water heater must only be carried out by qualified
personnel. Phone Rheem Service or their nearest Accredited Service Agent.
Note: The annual service and routine replacement of any components, if
required, are not included in the Vulcan warranty. A charge will be made for this
work. Only genuine replacement parts should be used on this water heater.
The annual service includes the following actions:
Inspect and flush the temperature pressure relief valve.
Inspect and flush the expansion control valve (if fitted).
Check and if necessary adjust the inlet gas pressure.
Check the piezo igniter, gas control and thermocouple.
Check the operation of and clean the pilot light and main burner.
Visually check the unit for any potential problems.
Inspect all connections.
Check the drain line from the safe tray (if one is installed) is not blocked.
Note: The water heater may need to be drained during this service. After the
completion of the service, the water heater will take some time to reheat the
water. Hot water may not be available for a while.

REGULAR CARE
10
MAJOR FIVE YEAR SERVICE
It is recommended a major five year service be conducted on the water heater.
Warning: Servicing of a water heater must only be carried out by qualified
personnel. Phone Rheem Service or their nearest Accredited Service Agent.
Note: The five year service and routine replacement of any components, such
as the anode and relief valve(s), are not included in the Vulcan warranty. A
charge will be made for this work. Only genuine replacement parts should be
used on this water heater.
The major service includes the following actions:
Replace the temperature pressure relief valve.
Inspect and flush the expansion control valve (if fitted). If required, replace
the valve.
Inspect and if required, replace the anode.
If the anode is not replaced, it should be replaced within three years of this
service (refer to “Anode Inspection and Replacement” on page 14).
Check and if necessary adjust the inlet gas pressure.
Check the piezo igniter, gas control and thermocouple.
Check the operation of and clean the pilot light and main burner.
Visually check the unit for any potential problems.
Inspect all connections.
Check the drain line from the safe tray (if one is installed) is not blocked.
Note: The water heater may need to be drained during this service. After the
completion of the service, the water heater will take some time to reheat the
water. Hot water may not be available for a while.

REGULAR CARE
11
MINOR SIX MONTH MAINTENANCE
It is recommended minor maintenance be performed every six months by the
dwelling occupant.
The minor maintenance includes:
Operate the easing lever on the temperature pressure relief valve. It is very
important you raise and lower the lever gently. Refer to “Temperature
Pressure Relief Valve” on page 12.
Warning: Exercise care to avoid any splashing of water, as water
discharged from the drain line will be hot. Stand clear of the drain line‟s
point of discharge when operating the valve‟s lever.
Operate the easing lever on the expansion control valve (if fitted). It is very
important you raise and lower the lever gently. Refer to “Expansion Control
Valve” on page 11.
Check the drain line from the safe tray (if one is installed) is not blocked.
EXPANSION CONTROL VALVE
In many areas, including South Australia, Western Australia and scaling water
areas, an expansion control valve is fitted to the cold water line to the water
heater. The expansion control valve may discharge a small quantity of water
from its drain line during the heating period instead of the temperature pressure
relief valve on the water heater.
Operate the easing lever on the expansion control valve once every six
months. It is very important you raise and lower the lever gently. The
expansion control valve should be checked for performance or replaced at
intervals not exceeding 5 years, or more frequently in areas where there is a
high incidence of water deposits.

REGULAR CARE
12
TEMPERATURE PRESSURE RELIEF VALVE
This valve is near the top of the water
heater and is essential for its safe
operation. It is possible for the valve to
release a little water through the drain
line during each heating period. This
occurs as the water is heated and
expands by approximately 1/50 of its
volume.
Continuous leakage of water from the
valve and its drain line may indicate a
problem with the water heater (refer to
“Temperature Pressure Relief Valve
Running” on page 18).
Warning: Never block the outlet of
this valve or its drain line for any
reason.
Operate the easing lever on the
temperature pressure relief valve once
every six months. It is very important
you raise and lower the lever gently.
Warning: Failure to do this may
result in the water heater cylinder
failing.
Warning: Exercise care to avoid
any splashing of water, as water
discharged from the drain line will be
hot. Stand clear of the drain line‟s point
of discharge when operating the
valve‟s lever.
If water does not flow freely from the drain line when the lever is lifted, then the
water heater must be checked. Phone Rheem Service or their nearest
Accredited Service Agent to arrange for an inspection.
The temperature pressure relief valve should be replaced at intervals not
exceeding 5 years, or more frequently in areas where there is a high incidence
of water deposits (refer to “Water Supplies” on page 13).
water
heater
water
heater
drain
line
lift until water
flows from the
drain line –
lower gently

13
WATER SUPPLIES
This water heater must be installed in accordance with this advice to be
covered by the Vulcan warranty.
This water heater is manufactured to suit the water conditions of most public
reticulated water supplies. However, there are some known water chemistries
which can have detrimental effects on the water heater and its operation
and / or life expectancy. If you are unsure of your water chemistry, you may be
able to obtain information from your local water supply authority. This water
heater should only be connected to a water supply which complies with these
guidelines for the Vulcan warranty to apply.
ANODE
The vitreous enamel lined cylinder of the water heater is only covered by the
Vulcan warranty when the total dissolved solids (TDS) content in the water is
less than 2500 mg/L and when the correct colour coded anode is used. If an
incorrect colour coded anode is used in the water heater, any resultant faults
will not be covered by the Vulcan warranty. In addition, the use of an incorrect
colour coded anode may shorten the life of the water heater cylinder.
The correct colour coded anode must be selected and fitted to the water heater
in accordance with the following advice and the Anode Selection chart on
page 14 for the Vulcan warranty to apply to the water heater cylinder.
Total Dissolved Solids
Anode colour code
0 –40 mg/L
Green
40 –150 mg/L
Green or Black
150 –400 mg/L
Black
400 –600 mg/L
Black or Blue
600 –2500 mg/L
Blue
2500 mg/L +
Blue (no cylinder warranty)
The changing of anodes must be carried out by a qualified person.
Note: Some water analysis reports may state the conductivity of the water
rather than the level of total dissolved solids. Conductivity, measured in
microsiemens per centimetre (µS / cm), is directly proportional to the TDS
content of the water. TDS, in mg / L, is approximately 70% of the conductivity in
µS / cm.

WATER SUPPLIES
14
CONDUCTIVITY - µS/cm
TOTALDISSOLVEDSOLIDS & CONDUCTIVITY
(vitreous enamel lined water heater cylinder)
40 150 400 600 TOTAL DISSOLVED SOLIDS (TDS) - mg/L
ANODE SELECTION
warranty applies to a vitreous enamel lined water heater cylinder if the
correct coloured anode is used for the TDS / conductivity level of water
2500
3570
no warranty
applies
to a vitreous
enamel lined
water heater
cylinder
Blue
Black
Green
60 215 570 860
0
0
Blue
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 “Major Five Year
Service” on page 10) then the maximum time after installation when the anode
should be replaced for this gas 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. In areas where this is likely to
occur, the installer should instruct the householder on how to dissipate the gas
safely.
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.

WATER SUPPLIES
15
SATURATION INDEX
The saturation index (SI) 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.
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 Vulcan warranty to apply to the temperature
pressure relief valve and water heater cylinder.
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 15.
Refer to the cold water connection detail on page 28 for the position of the
expansion control valve.
-1.0
no warranty applies to a:
temperature pressure relief valve or a
water heater cylinder unless an
expansion control valve is fitted.
SATURATION INDEX (SI)
GAS STORAGE WATER HEATERS
WITHIN WARRANTY
SPECIFICATION
SATURATION INDEX
(calculated @ 80°C water temperature)
+0.4 +0.80
very corrosive very scaling
scaling
corrosive

WATER SUPPLIES
16
CHANGE OF WATER SUPPLY
The changing or alternating from one water supply to another can have a
detrimental effect on the operation and / or life expectation of a water heater
cylinder and a temperature pressure relief valve.
Where there is a changeover from one water supply to another, e.g. a rainwater
tank supply, bore water supply, desalinated water supply, public reticulated
water supply or water brought in from another supply, then water chemistry
information should be sought from the supplier or it should be tested to ensure
the water supply meets the requirements given in these guidelines for the
Vulcan warranty to apply.
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
Vulcan warranty will not cover any resultant faults on the components listed
below:
Water Chemistry
Component
Total Dissolved Solids (TDS) > 2500 mg/L
water heater cylinder
Total Dissolved Solids (TDS)
not suitable for anode type
water heater cylinder
Saturation Index (SI) > +0.4
(if expansion control valve is not fitted)
water heater cylinder
temperature pressure relief valve

17
SAVE A SERVICE CALL
Check the items below before making a service call. You will be charged for
attending to any condition or fault that is not related to manufacture or failure of
a part.
NOT ENOUGH HOT WATER (OR NO HOT WATER)
Are you using more hot water than you think?
Is one outlet (especially the shower) using more hot water than you think?
Very often it is not realised the amount
of hot water used, particularly when
showering. Carefully review the family‟s
hot water usage.
Have your plumber fit a flow control
valve to each shower outlet to reduce
water usage.
Pilot flame alight?
Check the pilot flame is burning by
removing the access cover. Relight the
pilot flame according to the lighting
instructions.
Refer to “Lighting the Water Heater”on page 33.
Temperature pressure relief valve running
Is the relief valve discharging too much water?
Refer to “Temperature Pressure Relief Valve Running” on page 18.
Thermostat setting
Ensure the thermostat setting is appropriate. You may choose to adjust the
thermostat upwards to gain additional hot water capacity.
Warning: Hotter water increases the risk of scald injury.
Water heater size
Do you have the correct size water heater for your requirements?
The sizing guides in the sales literature suggest average sizes that may be
needed.
WATER NOT HOT ENOUGH
You may find that due to heavy hot water usage the water temperature may be
lower than normally expected.

SAVE A SERVICE CALL
18
TEMPERATURE PRESSURE RELIEF VALVE RUNNING
Normal Operation
It is normal and desirable this valve allows a
small quantity of water to escape during the
heating cycle. However, if it discharges more
than a bucket full of water in 24 hours, there
may be another problem.
Continuous dribble
Try gently raising the easing lever on the
relief valve for a few seconds (refer to
“Temperature Pressure Relief Valve” on
page 12). This may dislodge a small particle
of foreign matter and clear the fault. Release
the lever gently.
Steady flows for long period (often at night)
This may indicate the mains water pressure sometimes rises above the
designed pressure of the water heater. Ask your installing plumber to fit a
pressure limiting valve.
Warning: Never replace the relief valve with one of a higher pressure
rating.
Heavy flows of hot water until the water heater is cold - then stops
until water reheats
The gas control must be turned off using the knob on top of the gas control
thermostat (refer to “Close Down Procedure” on page 35). Phone Rheem
Service or their nearest Accredited Service Agent to arrange for inspection.
EXPANSION CONTROL VALVE RUNNING
If an expansion control valve is fitted in the cold water line to the water heater
(refer to page 28)it may discharge a small quantity of water instead of the
temperature pressure relief valve on the water heater. The benefit is that
energy is conserved as the discharged water is cooler.
CAN’T LIGHT THE PILOT FLAME
Is there gas to the water heater?
Check the gas isolation valve on the gas
supply line is open.
Is there a normal gas supply to the rest of
the house?
Try lighting another gas appliance to check. If
there is no gas, call the gas supplier.

SAVE A SERVICE CALL
19
WATER HEATER APPEARS TO BE LEAKING
When the water heater is first lit, or after a large usage of hot water,
condensation may form on the burner of the water heater. This is quite normal,
especially in winter months and will dry off as the water is heated.
HIGHER THAN EXPECTED GAS BILLS
Should you at any time, feel your gas account is higher than expected, we
suggest you check the following points:
Is the relief valve running excessively?
Refer to “Temperature Pressure Relief
Valve Running” on page 18.
Is one outlet (especially the shower)
using more hot water than you think?
Refer to “Not Enough Hot Water” on
page 17.
Is there a leaking hot water pipe,
dripping hot water tap, etc?
Even a small leak will waste a
surprising quantity of hot water and gas.
Replace faulty tap washers, and have
your plumber rectify any leaking pipe
work.
Has there been an increase in hot water usage?
An increase in hot water usage will result in an increase in water heater
operation.
Has your water heating tariff rate been increased by your gas retailer since
your previous account?
IF YOU HAVE CHECKED ALL THE FOREGOING AND STILL BELIEVE YOU
NEED ASSISTANCE, CALL RHEEM SERVICE OR THEIR NEAREST
ACCREDITED SERVICE AGENT.

20
INSTALLATION
THIS WATER HEATER IS FOR OUTDOOR INSTALLATION ONLY.
THIS WATER HEATER IS NOT SUITABLE FOR POOL HEATING.
Check the water heater is suitable for the gas type available.
(refer to the rating label on the water heater)
INSTALLATION STANDARDS
The water heater must be installed:
by a qualified person, and
in accordance with the installation instructions, and
in compliance with Standards AS/NZS 3500.4, AS 5601 or AS/NZS 5601.1,
as applicable under local regulations, and all local codes and regulatory
authority requirements.
In New Zealand, the installation must also conform with NZS 5261, as
applicable under local regulations, and the New Zealand Building Code.
All packaging materials must be removed from the water heater prior to its
installation. This includes the removal of the cardboard base of the carton from
the underside of the water heater.
WATER HEATER APPLICATION
This water heater is designed for use in a single family domestic dwelling for
the purpose of heating potable water. Its use in an application other than this
may shorten its life.
If this water heater is to be used where an uninterrupted hot water supply is
necessary for the application or business, then there should be redundancy
within the hot water system design. This should ensure the continuity of hot
water supply in the event that this water heater was to become inoperable for
any reason. We recommend you provide advice to the system owner about
their needs and building backup redundancy into the hot water supply system.
Note: AS 3498 requires that a water heater provides the means to inhibit the
growth of Legionella bacteria in potable water. This water heater can satisfy
this AS 3498 requirement provided it is operating and the thermostat setting is
60°C or higher, including when it is used as an in-series booster water heater
for a solar water heater.