Chirana Chirolog sv: Leak test fails at the bag connection stage
What happened
On an anaesthesia/ventilation machine, the leak test fails at the bag connection step with an error, so the unit cannot be brought into operation. Reported in the case.
What was checked
- Compared the Stand By graphs from photos taken on site
- Checked the flow sensor, breathing circuit and test lung
- Disconnected the tubing from the sensor on the board to inspect the lines
- Checked the pressure sensors in the test line
- Re-ran the leak test with the oxygen supply connected
Cause
The cause was not the machine. In this case the engineers found that a 2 L test bag had been used instead of the 3 L bag required by the manual, and the unit passes the leak test only with the 3 L bag.
What was done
Replaced the test bag with the 3 L bag specified in the manual, and the leak test then passed. Running the test with the oxygen supply connected was also recommended. The case was solved.
Safety
Before returning the ventilator to use, run the full leak test and a ventilation check on a test lung with the accessories specified in the manual — an undetected leak directly affects the volume and pressure delivered to the patient.
Lesson: Before opening the machine, verify the test setup and accessories against the manual — a failed leak test can come from the wrong test bag rather than a faulty sensor.
Covered in the course: Ventilator Service — Level 2: Fault-Finding →
Written from an anonymised case shared by service engineers. It is not a manufacturer instruction and grants no authorisation. Independent note; names are trademarks of their owners.