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If a pressure limiting valve is installed on the cold water line to the water heater
and the cold water line to a temperature limiting device branches off before this
valve or from another cold water line in the premises, then a pressure limiting
valve of an equal pressure setting may be required prior to the temperature
limiting device.
CIRCULATED HOT WATER FLOW AND RETURN SYSTEM
A Rheem 312025 model can be installed as a secondary water heater in the
circulated flow and return system and supplied from an Off-Peak or Extended
Off-Peak electric, or a heat pump or solar water heater. The flow and return lines
connect to the secondary water heater, not the Off-Peak or Extended Off-Peak
electric, heat pump or solar water heater. The secondary water heater makes up
for the pipe heat loss in the flow and return system.
Note: The thermostat 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
Circulated Hot Water Flow and Return Off-Peak Electric, Heat Pump
or Solar Water Heater
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 Clause G12 of the New Zealand Building Code 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.
diagram on page 28.
27
INSTALLATION
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