HOW YOUR WATER HEATER WORKS
11
TWIN ELEMENT OPERATION
This water heater has two heating units, each controlled by the temperature sensors and the control system.
One heating unit is near the top of the water heater and the other at the base. The two heating units are wired
for non-simultaneous operation, so only one heating unit can operate at a time.
•
Top heating unit
The top heating unit has priority under normal operation to heat the water
in the top portion of the tank.
When there is less than 40 litres of hot water in the tank, the top heating
unit will energise to heat the top 45 litres to a temperature of 70°C using
utility grid supplied electricity during normal operation.
•
Bottom heating unit
The bottom heating unit is a triple blade multi-stage power input heating
unit. It is activated under normal operation after the top heating unit has
heated the water in the top portion of the tank.
The bottom heating unit heats the water in the lower portion of the tank to
a temperature of 70°C during normal operation, in response to a
requirement from the electricity utility or during periods of excess solar PV
power generation.
Note:
AS 3498 requires that a water heater provides the means to inhibit
the growth of Legionella bacteria in potable water. This requirement is met
if at least 90% of the stored water is heated to 60°C once every seven
days. If this does not occur during normal operation, the water heater will
enter Safety Compliance mode and use utility grid sourced electricity to
satisfy this requirement with heating via the bottom heating unit.
•
Electrical connection
The utility grid sourced power supply to the water heater must be a 24 hour Continuous / Domestic Time
of Use type. A separately metered controlled load supply, i.e. Off-Peak / time controlled, is not suitable.
NOTE: Power must be available to the heating units
’ circuit at all times for this water heater to operate
as designed.
