Liquid Logic V3 Vehicle System Controller

Liquid Logic V3 Vehicle System Controller

The Liquid Logic V3 presented a number of challenges in its development. It was intended to be the most complete and sophisticated WFP controller on the market. As such it needed to incorporate a number of new technologies not seen before in the WFP arena.

The Liquid Logic V3 was to incorporate a number of sensors:

TDS senors to measure water purity

  • TDS for RO
  • TDS for DI

Pressure sensor to monitor filter ageing

  • Flow sensors to measure water usage
  • Level sensors to control tank filling
  • Temperature sensors for hot water control​​

And a number of outputs:

  • +12V delivery pump
  • Filling solenoid valve
  • Autoflush solenoid valve
  • Optional recirculation solenoid valve​

In addition to all this the unit was also to include

  • Second battery split charger
  • On/off and flow adjustment by radio control
  • Frost protection

The first problem was how to present this increase in information to the user. The solution was to move to a backlit character LCD. This provides ample characters to give the users all the information that they need to operate the system.


The Liquid Logic V3 required an all-new black IP65 enclosure. Machined on Spring's CNC machines, the new enclosure is only a little larger than the standard one and yet the additional space allows for three IP65 glands to be fitted, which makes for effective cable management. Sensible functional grouping with colour-coding makes cable identification a simple matter for the system installers.


A careful and studied execution in board layout was needed to cope with the additional sensor inputs and outputs and to ensure that the inclusion of so much technology in such a small enclosure did not create any problems. New hardware interfaces and software drivers were developed for reading pressure sensors and flow meters. Once completed these were seamlessly integrated into the design to provide the user with all the information they should need.


One of the most significant parts of the development was the design of the UI (User Interface) as the Liquid Logic V3 had to achieve an operation consistent with other Spring controllers with which the WFP market was already familiar, whilst providing easy access to the additional features and capabilities. The resulting UI is therefore based on the V11 but allows simple and quick access to all the advanced features of the Liquid Logic V3. Standard user functions, such as pump speed, user selection, calibration and filling, all use the standard key combinations from the V11 range, making the move from a V11 to a Liquid Logic V3 as easy as possible. However, a simple settings menu was added. This allows the user to simply scroll through the various additional features, to select each one and to adjust as required.


New features include:

  • Adjustable frost stat temperature
  • Adjustable frost pump recirculation
  • Adjustable low water pressure warning
  • Adjustable max RO TDS
  • Adjustable max DI TDS

The settings menu allows the user to set and adjust all these new functions as well as all the existing ones, such as low battery shutdown override, frost stat on/off, heater on/off and so on. When running in normal use the controller makes it simple to flick through selected flow, TDS readings, leisure and van battery voltages, water usage and pressure and temperature screens.


The end result is one of the most capable pump controllers available.