Fuel Flow Gauge & Meter FAQ's 

69 mm (w) x 40 mm (d) x 70 mm (h)

87mm (w) x 30 mm (d) x 80 mm (h) - please refer diagram below

71.5 mm (w) x 56 mm (h) - please refer to diagram below.

The screens on the Flush Mount & Surface Mount Water Tank Gauges have an IP rating of IP66, as does the front of the Bluetooth Module. However do not submerge the whole gauge in water as this will cause it to stop working. In addition, the sender unit is waterproof but take care to install it in a location where it is away from impact from road debris, stones etc.

There is a small LTR or GAL next to the amount displayed to show which mode you are in Disconnect the power (or batteries) Press and hold the “PROG” button while reconnecting the power Release the button after you hear the long beep. The display will be switched (from LTR to GAL, or GAL to LTR) Wait until the screen turns off and the unit will memorise the setting

The “HXX" will display sometimes. This is not a fault. It is the code for the different senders. If this setting has been accidentally changed it can be easily reset by pressing both buttons at the same time and scrolling through until it shows the relevant “HXX” again. Pressing both buttons will also reset the amount to the programmed amount. Refer to the table below for Sender Specifications:

If your display is out by a large amount it is usually because you have managed to change the sender codes Press both buttons at the same time and release - H22 should be displayed. If “H22” is not displayed, keep pressing and releasing the "DISPLAY" button until “H22” is displayed. Wait until the screen turns off and the unit will memorise the setting. This is the correct code for the ½’ sender supplied with these models. Also ensure the display is not reading in gallons instead of litres. If this is the case refer to FAQ - Changing from litres to gallons or gallons to litres.

Ensure you do not turn the display "POWER OFF" until it has gone to sleep - this takes approx 10 seconds. The remaining quantity is only recorded in memory after the display has gone to sleep.​

Check that the snake at the top of the screen is moving when water flows. If it is moving this is a normal condition. Check if the water is flowing in the direction of the arrow on the sender. If it is not flowing in the direction of the arrow, refit sender in direction of flow. Check that nothing is caught in the implellar, such as teflon tape. It could be something as little as shavings from holes drilled in the tank at some stage. Make sure you remove debris carefully. Have the sender wires been cut and joined? If they have this would cause this issue and your warranty is void If you have fitted extension leads, unplug them, then remove sender and plug into 1.4mt lead from display and blow into lightly to check. Press both buttons at the same time and release - H22 should be displayed. If “H22” is not displayed, keep pressing and releasing the "DISPLAY" button until “H22” is displayed. Wait until the screen turns off and the unit will store the setting. This is the correct code for the ½" sender supplied with these models. Screen turns on and snake at top of screen moves but amount does not change. Refer above. Check if litre is displayed in the bottom right hand corner. If displaying in gallons please refer to FAQ - Changing from litres to gallons or gallons to litres?

In the unlikely event that this happens, disconnect power. Press the "DISPLAY" button to release any holdover charge in the capacitors. Wait 30 seconds and reconnect power. Display will reboot and go through self check and restart.

This can sometimes happen for the following reasons: If the magnet in the sender stops next to the Hall Effect sensor inside the sender unit and there is any slight movement in the RV. If this is the case, the simple solution is to open and close a tap quickly to move the impeller to a different position. Turn the pump off if the 12v power for the display is coming from the same circuit (this is the recommended power source for the H2F-FM 12v model). If the fuel pipe does not have any fuel in it, however the impeller is free to turn in air this could cause this issue. The reason this sometimes happen is if the sender is fitted to the inlet side (suction side) of the pump. In this case turn the display power off. All settings and quantity will be stored. If the sender is fitted to the suction side of pump and there is a slight drop in pressure caused by an old pump (unable to hold prime), air getting into line or severe corrugations could all cause the unit to flash on. This is another reason we recommend the sender be fitted to the pressure side of pump.

For AA battery models, check that the batteries are fitted the right way and are fresh/charged. Remove and replace correctly. For 12V Models, ensure the cables are not connected in reverse. Connect red wire to positive and black to negative.

Up to 6 leads may be joined to make 9.8m in total length.

Sender leads cannot be cut and joined – this will void your warranty. Extension leads must be used.

The maximum monitoring capacity is 99,999 litres/gallons.

Using the example of having 3 x 100 litre tanks - the gauges can read either way depending on the way you set it up. You can set the gauge up to read one tank at a time, ie 1 x 100 litres, then when that tank is empty you can set it up to read the next fuel tank and so on. Alternatively, you can set it up to read the whole combined amount of the three tanks totalling 300 litres.

No only 1 sender can be used.

We suggest the following methods to resolve this problem: Clear the cache and data of the Google Play Store. Attached below is the procedure on how to clean the cache and data of the Google Play Store. This may sometimes cause the problem. Use the Google Play Store in the internet browser instead of the APP to download the eFlow. Use the APK attached. (zipped file)

The gauge is designed for battery power power primarily and if you connect direct to 12v you can damage your gauge with excess power. Its is important to use the Topargee 12v adaptor as it have been thoroughly tested to compliment the gauge. 12v batteries can often produce more power even spike damaging the communication module on the gauge. The batteries last for 12months and provide a reliable power solution. If you prefer 12v please use https://www.topargee.com.au/product-page/12v-adapter, and other power solution may void your warranty.

Go to Setting > Google > Location > Choose OFF Quit from Setting > Quit from eFlow and enter it again eFlow will ask you location permission > choose YES

If you are running Android 13 or higher use the latest app on-line with Google Play. If you are running Adroird 12 or earlier version, use the link below: https://drive.google.com/file/d/1zayRvsLNZwNDHldF3J8dHYZSFzSn3HZy/view?usp=share_link

Please ensure you only use a Topargee 12V lead when connecting to 12V. Direct 12V will cause your gauge to function incorrectly. It has also been known to burn the board on the gauge rendering it unusable. The double AA battery pack is only a 3v pack so connecting 12v without the adaptor will damage your gauge.

Go to Setting > Apps > eFlow > Storage Choose CLEAR DATA & CLEAR CACHE Quit from Setting > Quit from eFlow and enter it again

When designing our gauges we wanted to keep the operation as simple as possible. You can always set your volume on the gauge to any amount without just resetting it to full. For example if you have a 200 litre tank and it goes down to 150 litres and you add the extra 20 litres, change your tank size in the device to 170 litres and off you go with your 170 litres of fuel. Then when you refill and you top the tank, reset the gauge volume to 200 again.

The H2F-BT12 Bluetooth Water Tank Gauge is only compatable with Android 8 or later.

Download this file and follow the instructions

On average the batteries last approx. 2 years with normal use with the Surface Mount Fuel Flow Gauge and approx. 12 months with the Bluetooth Fuel Flow Gauge Model.

The FM Flush Mount replaced the RM model approx 6 years ago. It is 12v only, has a larger backlit screen and must be fitted at eye height or above as polarised, therefore you can read it in bright daylight. Please refer to the Product for full list of Specifications.

This will happen if the battery voltage drops below 9v. When quantity reaches 000 or -001 the display will turn red and the buzzer will sound.

Yes you would just need to get a 24-12v Transformer/Convertor.

The blue screen or HHH is generally caused by the power being too high. When the power gets over 12v it can cause the screen to not work. Disconnect the power from the gauge, DO NOT disconnect the power from the van as this will not resolve the issue. This will allow the solenoid to reset gauge, activating the screen again. We would recommend checking you power levels to ensure it is no more than 12v. A lot of lithium batteries are between 13v - 15v. If you are still experiencing issues when connecting the power, install a reducer on your positive wire.

When the Flush Mount is powered on, the microprocessor software will check if all of the lights, blue and red as well as the segments on the LCD are functional or not. This is why the screen flashes blue and red when turning on. See video below as an example of a normal power up

Put simply this cannot be done.

The gauge only reads one way and therefore will not register when you are filling the tank. Once the tank is filled press the reset button and it will change back to your pre-programmed amount. Please note the sender unit is fitted after the pump.

The minimum flow is 1.5 LPM. To test it you will need to have the tank nearly empty then time it with a 2 litre milk bottle. If it is over 1.5 LPM then you will have no problems.

If you have no room after the pump, the sender can be fitted before the pump. The main reason we don't recommend this is if you do not tighten all connectors properly and there is a tiny pin hole, air will enter the hose line and the water will drain back into the tank. If the sender is fitted on the pressure side any leaks become obvious. However, if fitted correctly the sender can be fitted either side of the pump.

The H2F-FM Flush Mount Water Tank Gauge will work with a hand pump. We are aware that a lot of the FM water gauges are fitted in the Jayco Camper Trailers. Please note the minimum flow is 1.5 LPM.

A Fuel Flow Gauge will count down from a pre-determined amount. As an example if you set your gauge to 100 litres. Once the fuel goes through the sender the gauge will start courting down from 100, 99, 98, 97 etc. A Fuel Flow Meter also known as a Totaliser will count up.   As an example once the fuel goes through the sender the meter will start courting up from 0, 1, 2, 3, 4 etc.