27
Operation Type
W Models
H Models
3
Relief Valve Setting (kPa)
1000 (850)
1
415
Expansion Control Valve (ECV)
2
Setting (kPa)
850 (700)
1
NA
Minimum Supply Pressure
System water temperatures up to 65
o
C (kPa)
70 (7m)
70 (7m)
System water temperatures above 65
o
C (kPa)
120 (12m)
120 (12m)
Maximum Supply Pressure
without ECV² fitted
800 (680)
1
330
with ECV² fitted
680 (550)
1
NA
¹ Figures in brackets are to be used if an RT stainless steel storage tank is utilised in the system.
² Expansion control valve is not supplied with the water heater.
3
H models used for high temperature DHW applications follow pressure limitations of W models.
Table 7: Water Pressure Specifications
HOT WATER DELIVERY (WATER HEATING APPLICATIONS)
This water heater may deliver water at high temperature. Refer to the Plumbing Code of Australia,
local requirements and these installation instructions to determine if additional delivery temperature
control is required.
Where a temperature limiting device is installed adjacent to the hot water storage tanks, the cold water
line to the temperature limiting device can be branched off the cold water line either before or after the
isolation valve, pressure limiting valve and non-return valve to the storage tanks. If an expansion control
valve is required, it must always be installed after the non-return valve and be the last valve prior to the
water heating system.
If a pressure limiting valve is installed on the cold water line to the water heating system 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.
REDUCING HEAT LOSSES (WATER HEATING APPLICATIONS)
The cold water line to and the hot water line from the storage cylinder must be insulated in accordance
with the requirements of AS/NZS 3500.4. The insulation must be weatherproof and UV resistant if
exposed.
Keep temperature settings down. Lower temperatures reduce heat losses and prolong storage cylinder
life. Do not set the controlling electronic thermostat above 65°C unless it is necessary. A BMS can be
used to switch off the water heater during hours or days when it is not in use.
EXPANSION CONTROL VALVE
Local regulations may make it mandatory to install an expansion control valve (ECV), or expansion
vessel, in the cold water line to the water heating system. In other areas, an ECV or expansion vessel
is not required unless the saturation index is greater than + 0.4 (refer to
“Water Supplies” on page 18).
However, an ECV may be needed in a corrosive water area where there are sufficient quantities of
silica dissolved in the water.
The ECV or expansion vessel must always be installed after the non-return valve and be the last valve
installed prior to the water heater (refer to Fig 4 on page 42). A copper drain line must be run separately
from the drain of the ECV.
RELIEF VALVE DRAIN
A copper drain line must be fitted to each relief valve (Pressure Relief and ECV, if fitted) to carry the
discharge clear of the water heater. Connect the drain line to the relief valve using a disconnection
