Rheem 491 Owner's Manual And Installation Instructions page 34

PIPE SIZES
This water heater is intended to be permanently connected to the water mains
and not connected by a hose-set. A braided flexible hose or semi-flexible
connector may be used for connection to the water heater, where permitted by
AS/NZS 3500.4.
To achieve true mains pressure operation, the cold water line to the water heater
should be the same size or bigger than the hot water line from the water heater.
The pipe sizing for hot water supply systems should be carried out by persons
competent to do so, choosing the most suitable pipe size for each individual
application. Reference to the technical specifications of the water heater and
local regulatory authority requirements must be made.
TEMPERATURE PRESSURE RELIEF VALVE
The temperature pressure relief valve is shipped either under the top flap of the
water heater carton or behind the front cover or in a plastic bag attached to the
water heater. The temperature pressure relief valve must be fitted before the
water heater is operated. Before fitting the relief valve, make sure the probe has
not been bent. Seal the thread with an approved thread sealant such as Teflon
tape - never hemp. Make sure the tape does not hang over the end of the thread.
The water heater has a temperature pressure relief valve connection on its left
hand side.
Screw the valve into the opening labelled "Relief Valve" (refer to the installation
diagram on page 30) leaving the valve outlet pointing downwards. Do not use a
wrench on the valve body - use the spanner flats provided. A copper drain line
must be fitted to the temperature pressure relief valve (refer to "Relief Valve
Drain" on page 35). If the water heater has a second relief valve fitting, refer to
"Left and Right Hand Side Water Connections" on page 33.
The valve must be insulated with closed
cell polymer insulation
(minimum thickness 9 mm) and the
insulation installed so as not to impede
the operation of
insulation must be weatherproof and
UV resistant if exposed.
The flexible insulation collar supplied
with the temperature pressure relief
valve meets these requirements and
must be placed over the body of the
valve (refer to the diagram on page 34).
or similar
the valve. The
34
USE TEFLON TAPE
FIT SUPPLIED INSULATION TO
VALVE AS SHOWN
flexible insulation collar
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