Before diagnosing issue, it's critical to understand why you believe the ultrasonic readings are incorrect. If you are comparing the ultrasonic readings to what the gauge is reading, it’s important to know that analog dial gauges on propane tanks can be up to 15% inaccurate and are much less reliable than ultrasonic readings. 

Fill Level Measurements Stuck at Low Percent

If you’re ultrasonic readings are stuck at a low percent, it is possible there is water or sediment at the bottom of the tank. This would cause the signal to bounce off these contaminants, making the Xact system would think there is product in the tank when there is none. Be sure to clean out any water and to remove any sediment that may have built up. Take the following steps to troubleshooting

  1. Make sure the tank is at least 20% full
  2. Apply fresh gel to to transducer
  3. Move to new location underneath tank (we recommend at least 4 feet away from original location)
  4. Scrape off any dirt, debris, or paint chips that could interfere with sonar 'PING' used to take measurements.
  5. Recalibrate and recommission unit.

Note: You may need to repeat step 2 several times to find ideal spot underneath tank. The goal is to find the "sweet spot" where the transducer finds the least amount of interference and is able to take an accurate measurement. 

Volatile Readings -- Fill Level Measurements are Jumping Around

Volatile swings in fill level measurements reported by the ultrasonic system could also be another sign of water/rust/sediment in the bottom of the tank. Proceed with the same troubleshooting steps listed in the above section.

“Not Valid Reading” Error – Empty Tank

Empty tanks will never work correctly.  The transducer works by sending a high-frequency signal through the bottom of the tank and then measuring how long it takes for that signal to bounce off the top of the liquid in the tank and be received by the transducer.  If the tank is completely empty the transducer signal never bounces back. If the bottom of the tank is clean inside (i.e., no water collected at the bottom of the tank and no sediment inside at the bottom of the tank) the signal will not bounce back and you will get an error.


Many readings that seem suspicious are due issues with the gauge “boot” or clip. These readings could show up in the following ways:

  • Readings are stuck at 50% fill level
  • Readings are stuck between 0-30% fill level

Check to see if it’s damaged, loose or clipped in all the way. When the Gauge Reader is by itself (not connected to the dial) it should read 50%. This will help us understand if the Gauge Reader is having problems or if the issue is with clipping into the dial or the dial itself.

It’s also important to make sure the gauge itself isn’t stuck or defective. Standard mechanical gauges, such as the Rochester float gauges, always have errors near their limits (i.e., between 0% and 10%, as well as 90% to 100%.)