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6.5.14 SO: Dry running factor
This sets the minimum dry running factor threshold below which the lack of water is detected. The dry
running factor is a non-dimensional parameter obtained by combining absorbed current and the pump power
factor. Thanks to this parameter it is possible to correctly establish when there is air in the impeller of a pump
or if the suction flow is interrupted.
This parameter is used on all multi inverter systems and on all systems without flow sensor. If the pump
functions only with one inverter and flow sensor SO is blocked and disabled.
The default value set is 22, however if necessary the user can change the parameter and set it between
10 and 95. To help the user with the setting, the page shows the dry running factor measured in real time
(in addition to the SO minimum dry running factor to be set). The value measured is shown in a box below
the name of the SO parameter and is called “SOm”.
In the multi inverter configuration, SO is a parameter which can be propagated between inverters but it is
not a sensitive parameter, i.e. it does not necessarily have to be the same for all inverters. When a
change in SO is measured the user is asked whether the value should be propagated to all the inverters.
6.5.15 MP: Minimum pressure pump stop due to water failure
This sets the minimum pressure pump stop due to water failure. If the system pressure reaches a pressure
below MP the lack of water is signalled.
This parameter is set on all systems without flow sensor. If the pump functions with flow sensor MP is
blocked and disabled.
The MP default value is 0.0 bar and can be set up to 5.0 bar.
If MP=0 (default), the dry running is detected by the flow or the dry running factor SO algorithm;
if MP is not equal to 0, the lack of water is detected when the pressure is below the MP value.
The lack of water alarm is detected only when the pressure goes below the MP value for the amount of time
set for the TB value, see par. 6.6.1.
In the multi inverter configuration, MP is a sensitive parameter therefore it must always be the same along
the chain of inverters in communication and when the value is changed it is automatically propagated to all
the inverters.
6.6 Technical Assistance Menu
From the main menu, press and hold “MODE” & “SET” & “+“ simultaneously until “TB” appears on display
(or use the b or – in the selection menu). This menu enables the display and modification of various
configuration parameters. The MODE button enables the user to scroll through the menu pages, while
b and – enable respectively to increase and decrease the value of the parameter concerned. To exit
the current menu and return to the main menu, press SET.
6.6.1 TB: Water failure block time
Entry of a water failure block delay time enables selection of the time (in seconds) taken by the inverter to
notify of low water levels on the electric pump.
Modifications to this parameter may be useful if a known delay exists between the moment in which the
pump is activated and the actual moment of supply. One example is that of a system where the electric
pump intake line is particularly long and is subject to small leaks. In this case it may occur that the pipeline
empties, and even if the water supply is regular, the electric pump takes some time to reload, deliver flow
and pressurise the system.