Water Tank Monitors (Dual)

Flows sensors can be inserted into (max 2) tank outlet pipes to measure the outflow of water from the tanks. The total outflow, as well as the water remaining in the tank, is reported on the mobile phone. Measurement of waterflow continues when the phone is switched off or is out of range. Tank capacity of up to 200L is supported.

 Can be attached to: 

Basic Flow Sensor
Basic Flow Sensor

The control unit can monitor and report on two water tank monitors which are functionally the same. Water passing out of a tank turns a little bucket wheel and fractions of rotation of this wheel are detected, counted and converted to litres of water by the electronics and programming. The flow sensor provides only data on the outflow of absolute litres but, with the help of user supplied data regarding tank capacity, as well as a signal that the tank has been newly filled, the app can report the percentage of tank capacity remaining in addition to reporting the total outflow since last fill.

Flow Sensor YF-B6
Flow Sensor YF-B6

The flow sensors are equipped with a thread of between 1" and ¾" BSP on both ends. There are reducing bushes commonly available at all hardware and builder's shops that bring this down in stages to 1/2 inch and even 1/4 inch, which is adaptable to all types of plumbing that are found in an RV.


The Flow Sensors

The flow sensor measures water flow by means of a bucket wheel or impeller in the water passage that generates Hall Effect impulses when turning at a rate proportional to the water flow. Several hundred of these impulses represent a litre of water passing through the sensor, the exact number depending on the model of flow sensor. Two popular sensors are supported -  the all-plastic FS400A and the brass-bodied YF-B6. The YF-B6 is more initially more expensive but, having ¾ coupling requires less reducers on installation.

Because these sensor have differing flow rates the controller's firmware is set up to serve one or the other.

Water Flow Monitor
Water Flow Monitor

The only maintenance it will ever need is being cleared of foreign matter clogging the bucket wheel or impeller. 

Clearing the Flow Count

The flow sensor will report every 3,5mL water that passes through it to the control unit. The control unit will add this count to a total kept in memory until the counter overflows or is cleared by instruction from the mobile phone. To keep an accurate track of water usage from a tank the outflow counter needs to be cleared every time the tank is filled. The user does this by quick (< 400Ms) double tapping the Tank Icon on the mobile phone screen. The phone will buzz briefly when the clear command is sent to the control unit, and the water usage total for that tank will reset within a few seconds. 

Water Used & Quantity Remaining

The normal display is for the app to show the percentage of tank contents remaining. While any water tank icon is pressed and held down the app will display instead the actual water drawn from that tank since the count was last cleared, as well as the tank capacity previously entered by the user (see below).

Setting the Tank Capacities

In order to successfully calculate the percentage of water remaining the app needs to know the total capacity of each tank.
To set the tank capacity: give the icon for the chosen tank a short (< 400mS) tap. The label for the other tank will go grey for 3 seconds, and during this time double tap the Caravan Pilot title.
A slide control will appear which will allow any value up a maximum of 200 Litres to be specified. Move the slider to the correct position and Save by tapping the Caravan Pilot title again.

If no double-tap on the Title is received within the 3 seconds the opposite tank label will return to its normal state.
Repeat for the other tank. 

When the Controller Loses Power 

Flow Sensor Installed
Flow Sensor Installed

To register the flow through the sensor the controller needs to be powered on. When the controller is without power water will flow through the flow sensor, but without being registered. However during normal operation the controller saves the flow count to non-volatile memory after every 5 litres of flow have that have been observed, so an unplanned power down can result in up to 5 litres of inaccuracy arising.

The latest flow count is also stored to non-volatile memory whenever the mobile phone app is paused or ended, assuming the controller is online to the phone. One of the last things the app does when it is paused or shut down is issue a command to the controller to store flow sensor data to non-volatile memory. Therefore it is advisable to close or pause the app while the controller is online immediately before switching the controller's power off.


As shown in the image at right the flow sensor is easily interposed in the tank outlet pipe using standard plumbing parts commonly available at any building or hardware shop. The sensor can be mounted in any orientation as long as the direction of water flow, which is clearly marked on the unit, is observed. It contains no serviceable parts and requires no maintenance or adjustments.



Flow Sensor w 2,5M cable & plug (but no hardware fittings)  each                       R300


Reducer bushes: From 1" to ¼" - six pieces - 4 plastic & 2 galvanised                  R200
Shipping usually together with other items.