Application Examples
Key for Wiring Diagram 3
eddi
device
Mains supply (230V AC from B16 circuit breaker or
13A fused spur)
Hot water cylinder
Heating element (max. 3.7kW)
Isolator (20A double pole)
Relay & Sensor Board (optional add-on for
eddi
)
Temperature probe (type PT1000) (optional)
Economy rate electric sense wiring (live only when
economy rate is available)
Functional Description
It is common for electric only households to employ dual tariff billing. This application enables automatic heating of water
when the economy tariff is available whilst also using any surplus generated power to heat the water.
The economy rate electricity can be time based or random, in either case,
eddi
be be set to heat the water at the economy
rate whenever possible, or at the economy rate only during certain times.
Heater 1 (the top immersion heater) (4) is heated with surplus power until the water at the top of the cylinder is hot and
the thermostat opens, then
eddi
will immediately switch over to Heater 2 (6); heating the bottom of the cylinder. This
makes the most of surplus energy as sometimes there will not be enough to heat the whole volume of the cylinder; it's best
to heat a smaller proportion (i.e. the top) first so there is some usable hot water, rather than a larger volume of warm water.
During heating of Heater 2,
eddi
will switch back to Heater 1 every 15 minutes to check if it can store any more heat.
When the water is fully heated, any surplus power will be exported,
eddi
will switch back the priority heater and check the
lower priory heater every 15 minutes.
If
eSense Input
is set to
Boost Enable 1&2
, the
BOOST TIMER
screen for either heater will include an option to
enable the boost timer only when the eSense input is live. In the
BOOST TIMER
, the
e
can be toggled on/off, if
e
is present,
the boost will activate only when the boost times are valid and the economy rate tariff is available.
Alternatively the eSense input can be used to active the boost whenever the economy tariff rate electricity is available,
regardless of boost times. To do this,
eSense Input
should be set to
Boost 1&2
. When using this option, the Boost
Timer is not needed.
If automatic sensing of economy rate times is not needed, the boost timer can be simply set to coincide with the economy
tariff times. In this case the Relay & Sensor Board (6) and the eSense wiring (8) are not required.
Installation of the temperature probes (7) is optional; the heaters' mechanical thermostat is used by
eddi
if temperature
readings are not required.
The
eddi
device should be labelled with a “dual supply” warning.
Settings Required
Menu Option
Settings
Main Menu
Settings…
Display…
Icons…
Heater 1:
Top Immersion
Heater 2:
Bottom Immersion
Priority…
Heater 1
Advanced Menu…
Relays &
Sensors…
Temperatures…
Set Temperatures as
required if using
temperature probes
eSense Input…
Boost…
Boost Enable 1&2/
Boost 1&2
operation and installation manual
eddi
37
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