INSTALLATION
41
CIRCULATED HOT WATER FLOW AND RETURN SYSTEM
A 571D270 model heat pump water heater should not be installed as part of a circulated hot water flow and
return system in a building.
If a circulated flow and return system is required, it is necessary to install a secondary water heater supplied
from the heat pump water heater. The flow and return lines connect to the secondary water heater, not the
heat pump storage tank. The secondary water heater makes up for the pipe heat loss in the flow and return
system and must be able to provide a hot water outlet temperature of at least 60°C.
Note: The thermostat or preset outlet temperature of the secondary water heater must always be set to
maintain a temperature of at least 60°C in the hot water flow and return line, including making up pipe heat
losses in the system.
Refer to the diagram Circulated Hot Water Flow and Return System – Heat Pump Water Heater on page 41.
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 – Heat Pump Water Heater
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