Auto Ventilation Leakage Test Failed

I have a problem with A8 Mindray Anesthesia Machine as the following:

when the stuff doing the test every morning the first result is failed (Red Screen) after checked all cables and connections .. etc., and redo the test the result is failed (Yellow Screen).

The stuff starts the operation with the yellow warning, after first operation the stuff redo the test result is pass and the device works normally rest of the day.

The only way to change the leakage test result from yellow warning (failed) to pass is when we start auto ventilation for a short time then redo the test again. After the first pass result the problem solved and we repeated the test more than one time and the test result is pass.

When we leave the device for the next day and redo the test in the morning the problem happens again (yellow warning).