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INSTALLATION – SOLAR STORAGE TANK
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 20.
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.
Circulated Hot Water Flow and Return System – Solar Water Heater
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