Technical data

INSTALLATION
16
CIRCULATED HOT WATER FLOW AND RETURN SYSTEM
If a storage tank is used with a primary water heating source and is to be installed as part of a circulated hot
water flow and return system, the primary heating source must be 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 16.
If a storage tank is used as part of a solar water heater, it 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 connect the return line after the solar preheat system and prior to the in-series booster water
heater supplied from the solar preheat system. The in-series booster water heater must be 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.
Temperature Limiting Device
A temperature limiting device cannot be installed in circulated hot water flow and return pipe work unless it is
specifically designed to do so, such as the Rheem Guardian warm water system.
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 or storage tank, depending on the
location of the return line connection on the water supply line to the water heater or storage tank, 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.
LEGEND
Circulated Hot Water Flow and Return System
Storage Tank with Primary Water Heater