Rheem 491 Owner's Manual And Installation Instructions page 25

The water heater is to be installed at ground or floor level and must stand
vertically upright on a stable base as acceptable to local authorities. The base of
the water heater is made of corrosion resistant material, and it may be placed
directly in contact with the supporting surface. It is not necessary to allow for free
air circulation under the base of the water heater.
Note: The water heater should not be placed in direct contact with a concrete
surface that is less than two months old and not fully cured as this may attack
the metal coating of the water heater base. A moisture barrier should be used
between the two surfaces in this instance. The barrier should extend at least
100 mm from the water heater and may be trimmed after two months.
Remember all local authorities have regulations about putting water heaters into
roof spaces.
SAFE TRAY
Where damage to property can occur in the
event of the water heater leaking, the water
heater must be installed in a safe tray.
Construction, installation and draining of a
safe tray must comply with AS/NZS 3500.4
and all local codes and regulatory authority
requirements. The safe tray must also meet
the requirements of Clause G12 of the New
Zealand Building Code. AS/NZS 3500.4 and
the NZBC also have particular requirements
when a safe tray must be installed.
MAINS WATER SUPPLY
Where the mains water supply pressure exceeds that shown in the table below,
an approved pressure limiting valve is required and should be fitted as shown in
the cold water connection diagram on page 32.
Model
Temp press relief valve setting
Expansion control valve setting*
Max. mains supply pressure
With expansion control valve
Without expansion control valve
* Expansion control valve not supplied with water heater
ERROR! REFERENCE SOURCE NOT FOUND.
491/492
1000 kPa
850 kPa
680 kPa
800 kPa
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