Rheem 874 Owner's Manual And Installation Instructions page 47

CIRCULATED HOT WATER FLOW AND RETURN SYSTEM
The Rheem 874 and 872 series continuous flow water heaters 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.
temperature controllers can not be installed with a water heater as part of a circulated hot water flow and
return system.
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.
Recirculated Hot Water Flow and Return - Continuous flow Gas Water Heater
REDUCING HEAT LOSSES
The hot water line from the water heater and the pipe work between the solar storage tank, if one is installed,
and the gas booster water heater must be insulated in accordance with the requirements of AS/NZS 3500.4.
The insulation must be weatherproof and UV resistant if exposed. The insulation must be fitted up to the
connections on the both the underside of the water heater and the solar storage tank.
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