Rheem Solar Thermosiphon Water Heater Technical Document

This water heater must be installed and serviced by a qualified person.
Please leave this guide with the householder or responsible officer.
Owner’s Guide
and
Installation Instructions
Solar Thermosiphon Water Heater
Stainless Steel Tanks
WARNING: Plumber –Be Aware
Use copper pipe ONLY. Plastic pipe MUST NOT be used.
It is a requirement of a solar water heater installation that all pipe work be in copper
and not plastic, due to the effects of high water temperatures.

PATENTS
This water heater may be protected by one or more patents or registered designs in the name of
Rheem Australia Pty Ltd.
TRADE MARKS
®Registered trademark of Rheem Australia Pty Ltd.
™ Trademark of Rheem Australia Pty Ltd.
Note: Every care has been taken to ensure accuracy in preparation of this publication.
No liability can be accepted for any consequences, which may arise as a result of its application.
WARNING: Plumber –Be Aware
The solar hot and solar cold pipe work between the thermosiphon solar storage tank and the solar
collectors are supplied in the pipe kit. The supplied copper solar hot and solar cold pipes MUST BE
used.
If the solar water heater is installed either on a metal roof or in a trafficable area, such as on an
accessible roof, then the solar hot and solar cold pipes must be insulated. The solar hot and solar
cold pipes may be required to be insulated to comply with local regulations.
If insulation is required, the full length of the solar hot and solar cold pipes MUST BE insulated.
The insulation must:
be of a closed cell type or equivalent, suitable for a solar water heating application and capable
of withstanding the temperature of the water or closed circuit fluid generated by the solar
collectors under stagnation conditions
The specification of the chosen insulation material should be checked with the insulation
manufacturer prior to installation as different materials may vary in temperature tolerance.
be at least 13 mm thick, however thicker insulation may be required to comply with the
requirements of AS/NZS 3500.4
be weatherproof and UV resistant
be fitted up to and cover the connections on both the solar storage tank and the solar collectors.
The insulation will offer corrosion protection to a metal roof against water runoff over the copper
pipe, assist in avoiding accidental contact with the solar pipe work as high temperature water or
closed circuit fluid can flow from the solar collectors to the solar storage tank and also reduce pipe
heat losses.
Plastic pipe MUST NOT be used, as it will not withstand the temperature and pressure of the closed
circuit fluid (indirect system) and water (direct system) generated by the solar collectors under
stagnation conditions. The solar collectors can generate extremely high water or closed circuit fluid
temperatures up to 150°C and high water pressure of 850 kPa. Plastic pipe cannot withstand these
temperatures and pressures and MUST NOT be used. Failure of plastic pipe can lead to the release
of high temperature closed circuit fluid and water and cause severe water damage and flooding.
There must be a continuous fall of a minimum 10° in the pipe work from the thermosiphon solar
storage tank to the solar collectors. The highest point of the solar cold pipe and solar hot pipe must
be where they connect to the thermosiphon solar storage tank, otherwise thermosiphoning will not
occur.
The solar water heater is to be isolated during the testing and commissioning of the heated water
reticulation system in a building, in accordance with Clause 11.1 and 11.3 (a) of AS/NZS 3500.4.

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CONTENTS
HOUSEHOLDER –We recommend you read pages 4 to 18.
The other pages are intended for the installer but may be of interest.
About Your Water Heater............................................................................................................ 4
Regular Care .............................................................................................................................. 11
Water Supplies........................................................................................................................... 13
Save A Service Call................................................................................................................... 16
Installation.................................................................................................................................. 19
Installation –Solar Collectors.................................................................................................. 34
System Assembly...................................................................................................................... 37
Connections –Plumbing .......................................................................................................... 48
Connections –Electrical........................................................................................................... 51
Multiple Installations................................................................................................................. 54
Commissioning.......................................................................................................................... 56
Draining The Solar Storage Tank............................................................................................. 59
Draining The Closed Circuit..................................................................................................... 60
Warranty..................................................................................................................................... 62

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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
Your Rheem®thermosiphon solar water heater is designed for both the solar collectors and the solar storage
tank to be roof mounted. The solar storage tank has a Colorbond jacket. The 52L tank (direct system) is
suitable for installation with Rheem Australis or Titan solar collectors (RL series) and the 52H tank (indirect
system) is suitable for installation with Rheem S200 (52H series), Australis or Titan solar collectors
(RLX series).
The 52L and RL series systems do not have freeze protection. These systems are not suitable for installation
in areas subject to frost or freeze conditions. Freeze conditions occur below 6°C. These systems have NO
WARRANTY for freeze damage (refer to “Terms of the Rheem Warranty” on page 62).
The 52H and RLX series systems are suitable for installation in areas subject to frost or freeze conditions.
Freeze conditions occur below 6°C. These systems have NO WARRANTY for freeze damage if non Rheem
approved closed circuit fluid has been used or if the closed circuit fluid has been incorrectly mixed (refer to
“Terms of the Rheem Warranty” on page 62).
This water heater is designed to be installed as an electric boosted solar water heater with its booster
heating unit connected to a power supply, however it may be installed with an in-series continuous flow or
storage booster.
If this water heater is installed with an in-series booster, then the electric booster heating unit will not be
connected to a power supply and the references to the electric booster heating unit, thermostat and boosting
controls in this Guide will not be applicable to the installation. For information relating to the function and
operation of the in-series booster, refer to the Owners Guide and Installation Instructions supplied with the
booster water heater.
SOLAR OPERATION
The Rheem solar thermosiphon system has its stainless steel solar storage tank installed on the roof directly
coupled to the solar collectors. The 52L and RL series are a direct solar hot water system and the 52H and
RLX series are an indirect solar hot water system with a heat exchanger in the solar storage tank.
52L, RL series: The solar storage tank and solar collectors are connected by copper pipe work and form an
open circuit which is filled with potable water.
52H, RLX series: The heat exchanger and solar collectors are
connected by copper pipe work and form a closed circuit which is
filled with closed circuit fluid. The closed circuit fluid is a solution
of a blue, non-toxic food grade propylene glycol concentrate
mixed with water. The closed circuit concentrate is used to lower
the freezing temperature of the closed circuit fluid and provides
protection against freezing. The closed circuit also provides
protection to the solar collectors and solar pipe work against
harsh water chemistry.
The solar water heater works on the simple scientific fact that hot
fluid rises. As the sun heats the water or closed circuit fluid in the
solar collectors, the increase in temperature causes the fluid to
rise through a copper pipe into the storage tank (52L, RL series)
or heat exchanger (52H, RLX series) where it transfers its heat
into the water in the solar storage tank. This allows cooler fluid
from the storage tank or heat exchanger to flow into the solar
collectors to be heated by the sun‟s energy. This process
continues while solar energy is available.
Automatic safety controls are fitted to the water heater to provide safe and efficient operation.

ABOUT YOUR WATER HEATER
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ELECTRIC BOOSTING
Water stored in the solar storage tank can be heated by an electric booster heating unit. The booster heating
unit is for heating the water at times of low solar energy gain, such as during very cloudy or rainy weather, or
during the colder months.
The amount of water heated by the raised booster heating unit of the thermosiphon solar storage tank is
90 litres (180 tank) or 150 litres (300 tank).
The thermosiphon solar water heater is most suited for the booster heating unit to be connected to either a
continuous, or a time of use, or an extended Off-Peak (overnight and day) electricity supply. A timer can also
be used to control the boosting periods and help maximise solar savings. Refer to “Booster Control” on
page 7.
The booster heating unit may be connected to an Off-Peak (overnight) electricity supply, however this will
only allow the booster to heat the water overnight. If this type of connection is considered, care must be
taken to ensure there is sufficient boost capacity to meet the household‟s full day and night‟s hot water
supply during periods of no or low solar gain, particularly in cold weather. There is also an increased risk of
temperature run down occurring, particularly in cooler weather (refer to “Temperature Run Down” on page 7).
The booster heating unit is controlled by an electric thermostat. The thermostat and its over temperature
energy cut out are mounted on the solar storage tank behind the front cover. The water temperature is
automatically controlled to the thermostat setting when the booster heating unit is energised.
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 21, a pressure limiting valve must be
fitted. The supply pressure should be greater than 350 kPa for true mains pressure operation to be achieved.
HOW HOT SHOULD THE WATER BE?
The temperature the system will operate at under solar radiation will
depend upon the level of solar radiation available, orientation and
inclination of the solar collectors, incoming cold water temperature
and volume of hot water used.
Under normal household use and average operating conditions, the
system may achieve a water temperature of approximately twice the
maximum daily outside air temperature. During periods high solar
radiation conditions and low hot water consumption, a system fitted
with an over temperature protection (OTP) system may heat the
water up to 85°C, whilst the water temperature could exceed 85°C
for a system without OTP.
During periods of low solar energy gain, the water temperature can
be boosted by the thermostatically controlled electric booster
heating unit. Refer to “Booster Control” on page 7.
Rheem recommends the thermostat is set at 60°C to maximise solar contribution.
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 the electric booster is
energised for a sufficient period each day and the electric booster thermostat setting is 60°C or higher.
If this water heater is installed with an in-series continuous flow gas booster, then this requirement of
AS 3498 can be satisfied provided the booster is energised, its preset outlet temperature setting is 70°C or
higher and a remote temperature controller is not used.
If this water heater is installed with an in-series storage booster, then this requirement of AS 3498 can be
satisfied provided the storage booster is energised and its thermostat setting is 60°C or higher.
maximum booster setting
maximum recommended
supply temperature to
bathrooms and ensuites
minimum booster setting