Rheem Electric Domestic Water Heater Installation And Owner's Manual page 19

Remember all local authorities have regulations about putting water heaters
into roof spaces.
SAFE TRAY
It is a requirement of AS/NZS 3500.4
that for a new installation, a water
heater be installed in a safe tray where
in the event of a leak, property may
otherwise be damaged. Construction,
installation and draining of a safe tray
must comply with the abovementioned
Standard.
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 installation diagram
Model
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
TANK WATER SUPPLY
If the water heater is supplied with water from a tank supply and a pressure
pump system is not installed, then the bottom of the supply tank must be at
least 1 m above the highest point of the hot water plumbing system, including
the water heater. Care must be taken to avoid air locks. The cold water line to
the water heater should be adequately sized and fitted with a full flow gate
valve or ball valve.
(refer to diagram on page
025 to 160 250 to 400
1400 kPa
1200 kPa
950 kPa
1120 kPa
19
INSTALLATION
27).
1000 kPa
850 kPa
650 kPa
800 kPa