DJI Agras Drone Pump Calibration Error

A pump calibration error appears when turning on the spray tanks. The drone will still be spraying but one pump may not be pushing out as much gal/min as it is supposed to, or as much as the other pump is.

Cause:

1. One of the pumps has gone bad.
2. The pumps just need to be recalibrated 
3. The pump may be clogged or gummed up and needs cleaned out. 
4. One of the spray lance setups may have a problem.
   1. This will most likely be the centrifugal motor. 
5. A hose could have a bad kink somewhere.
6. The spray module went bad.
7. The Spray Tank module went bad.

Diagnosing:

1. First, make sure the pumps are calibrated and there are no large kinks or holes in the lines.
   1. Recalibrate pumps, especially if a new one just got put on.
2. If allowable, put the spray tank in a different drone and see if the problem follows the tank or is on the original drone.
3. Take the cables leading to the pumps and switch them.
   1. If the error follows the cable switch (the cables are switched and it still reads the same pump) then that means the pumps and spray lance setups are fine and it is either a problem with the cable leading to the pumps, the spray tank module, or the spray module.
   2. If the error switches pumps, the original pump that was throwing the issue is the problem. 

Solutions:

1. If the problem stays with the pump, it will need to be replaced, and or cleaned out.
2. If the error is caused by the tank, but is not the pump, make sure everything is calibrated then try putting on a new spray tank board or the cables leading to the pumps.
3. If the error is caused by the drone it will most likely be caused by the spray module failing. 

1. If that does not fix it, make sure the spray tank cables have a good connection and try replacing that too.

Conclusion:

While there are several solutions and ways to diagnose this error, it is easy to begin troubleshooting and eliminating some of the causes. Being able to drop the tank into a different drone will really help in diagnosing a solution, and so will switching the cables on how they connect to the pumps. A good way to ensure the lifetime of a pump is to make sure that the owner rinses out the lines at the end of use if the drone doesn't sit for long. It does not always take long for some of the chemicals to begin to begin to solidify.