WATTrouter Mx - user manual
How to fit and setup the device
Page 26 from 82
SETTING UP COMBIWATT MODE
After you have successfully tested the main function, you may start to configure CombiWATT mode, provided a
low tariff signal is connected to the controller (it may be used even if single tariff rate is present – see notes
below). This can be done on the "Output settings" tab. CombiWATT mode provides constant daily energy
supply to the connected loads. This mode is indispensable if you need to heat up water but also e. g. if you use
a swimming pool filtering system during cloudy days or when your PV-plant is temporarily out of order. In
CombiWATT mode, energy is taken both from PV-plant and from public grid.
Determine the optimal value of energy in kWh for the connected load (for example for a boiler or immersion
heater), which you plan to supply the load with every day. For example, for a boiler it is suitable to determine
the value of electric energy based on the average consumption of hot water. Usually, electric energy necessary
to increase the temperature of hot water by 40°C equals to:
3600000
]
[
*
]
[
*
]
[
K
T
l
V
c
kWh
E
V
. If you enter it
into the formula you will get:
]
[
*
0464
.
0
]
[
l
V
kWh
E
. For a 180 liter boiler it will be 8.36 kWh. We
recommend to increase this value by the daily heat loss of the boiler and also to modify (reduce) the value
based on the actual average consumption of hot water.
Note:
If you are heating water for example, the controller does not "know" how hot the water in the boiler is
and therefore, the assumed values of the supplied electric energy may be higher than the actual delivered
energy (the boiler thermostat may shut it off at any time). If you want to count only real supplied energy to the
boiler then connect additional measurement for it according to Figure 8.
Mark the CombiWATT field for the relevant output (output must be activated, which means that the output
must be assigned with the relevant priority), enter the established value of the daily electric energy in kWh and
press the Write button. The configuration will be saved in the controller.
The CombiWATT mode is activated only if ALL the following conditions are met:
a.
The output is activated (priority has been assigned to the output - that means the output is
not in the "not used" status).
b.
PV-plant does not produce electric power (active powers at all measured phases are <= (less
or equal to the) CombiWATT production limit field).
c.
During the day, PV-plant did not supply the load with the required amount of energy, that is,
the field "Supplied energy" is lower than the value specified in the "CombiWATT [kWh]" field
for the relevant output.
d.
Low tariff signal has been detected (the info LED "low tariff" is red). Energy from public grid is
always consumed in CombiWATT only if low tariff is present. See note below to learn how to
configure this mode if you don't have double tariff rate.
e.
The "Time to activate CombiWATT"-field shows zero.
The CombiWATT mode is deactivated if some of the following conditions will apply:
a.
The value in the field "Supplied energy" reached the "CombiWATT [kWh]" value for the
relevant output.
b.
PV production has been detected at some of the measured phases (active power at some
measured phase is > (greater than the) CombiWATT production limit field).
c.
The low tariff signal is turned off.
Reset of energy counters (that is reset of values in the fields "Supplied energy")