Rheem 864 Series Owner's Manual And Installation Instructions page 50

INSTALLATION – WATER HEATER
CIRCULATED HOT WATER FLOW AND RETURN SYSTEM
A Rheem 864 627 model continuous flow water heater can be installed as part of a circulated hot water flow
and return system in a building.
Notes:

the preset outlet temperature setting of the water heater must be set to at least 60°C.
Water should not be circulated from a water heater with a temperature setting of less than 60°C.
In New Zealand an approved UV sterilisation or chlorine disinfection system may be used if the
temperature setting of the water heater is less than 60°C.

the return water temperature to the water heater must not be less than 55°C.
If the water temperature decreases by more than 5°C due to heat loss from the ring main, the preset outlet
temperature setting of the water heater must be set to above 60°C to ensure the return water temperature
is not less than 55°C.

temperature controllers should not be installed with a water heater as part of a circulated hot water flow
and return system, including when installed as part of an EZ Link System dual installation.
The circulator must be:

sized and set to provide a minimum flow rate of 3.0 L/min through the recirculated hot water flow and
return system, and

either thermostatically and / or timer controlled.
The circulator must not be set to operate continuously, i.e. 24 hours per day.
Warning: A Rheem 866 series continuous flow water heater must not be installed as part of a circulated
hot water flow and return system in a building.
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.
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