Troubleshooting Tank Water Sensors Reading Empty When the Tanks are Full

Published 10/20/2021

Question:

I replaced all of my holding tanks with new sensors. I replaced one sensor at a time so the wires would remain in correct positions. I did not disturb any other wires. All the tanks read empty when full. If it is a ground issue, I am confused on how that could happen since this was a straight foward job and nothing else was disturbed. There are no adjustments on my panel.

asked by: Richard C

Expert Reply:

When sensors like the Horst Miracle Probe Sensors # T21301VP are having improper readings of empty even when full, it is more often than not the result of a ground issue. The sensors will only read full when the tanks are full, completing the electrical circuit. If the ground is bad the circuit can not be completed and the sensors will not work.

I understand that you were careful not to disturb the wiring other than the sensor you were working on at the time. Unfortunately the nature of the beast with wiring is that you can still move it around enough to cause an issue, even when taking care. It could be something as simple as the ground wire has some corrosion so when you were moving the wires to attach the new sensors it was enough to break the ground off. A good ground will be metal on metal, if any debris is effecting the ground that could be playing a role as well. The best thing to do is to ensure that the ground wire has a secure clean connection and isn't broken. If that does not fix your issue then I would check the other wires to make sure they are all in good operable condition.

If after completing all of this you are still having issues please reach back out to me and I would be happy to dig into this further.

expert reply by: Scott S