Rheem Water Heater - Manual (Page 26)

INSTALLATION – SOLAR STORAGE TANK
26
If a pressure limiting valve is installed on the cold water line to the solar storage
tank and the cold water line to a temperature limiting device branches off
before this valve or from another cold water line in the premises, then a
pressure limiting valve of an equal pressure setting may be required prior to the
temperature limiting device.
CIRCULATED HOT WATER FLOW AND RETURN SYSTEM
A solar water heater should not be installed as part of a circulated hot water
flow and return system in a building. The benefits of solar gain will be
significantly reduced and energy gained from the sun lost through the pipe
work.
If a circulated flow and return system is required, it is necessary to bypass the
solar water heater and install a secondary water heater connected to the hot
water flow and return line and supplied from the solar water heater. The
secondary water heater must be a storage water heater able to provide a hot
water outlet temperature of at least 60
°C. Note: The thermostat must always
be set to at least 60 °C. Refer to the diagram on page 27.
Temperature Limiting Device
A temperature limiting device cannot be installed in circulated hot water flow
and return pipe work. The tempered water from a temperature limiting device
cannot be circulated.
Where a circulated hot water flow and return system is required in a building, a
temperature limiting device can only be installed on a dead leg, branching off
the circulated hot water flow and return pipe.
If circulated tempered water were to be returned back to the water heater,
depending on the location of the return line connection on the water supply line
to the water heater, then either:
• water will be supplied to the cold water inlet of the temperature limiting
device at a temperature exceeding the maximum recommended water
supply temperature, or
• when the hot taps are closed no water will be supplied to the cold water inlet
of the temperature limiting device whilst hot water will continue to be
supplied to the hot water inlet of the temperature limiting device.
These conditions may result in either water at a temperature exceeding the
requirements of AS/NZS 3500.4 being delivered to the hot water outlets in the
ablution areas, or the device closing completely and not delivering water at all,
or the device failing. Under either condition, the operation and performance of
the device cannot be guaranteed.