Specifications

ABOUT YOUR WATER HEATER
5
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