Dräger Fabius Tiro: bellows jerks at startup, ventilator fault
What happened
On power-up the ventilator bellows jerks briefly and then does not move; the screen shows a ventilator fault.
What was checked
- The engineers started from the ventilator drive motor: if the motor does not see its lower limit position, the drive can twitch once and refuse to run, so the limit-position sensors were the first thing to inspect.
- A flat CR2032 backup battery was the second suspect — when it dies, stored settings and options can be lost, so it was checked before deeper motor work.
- Pressure and PEEP calibrations per the manufacturer's service documentation were part of the plan, to be done by authorised personnel.
- After the battery change, the engineers planned to confirm that volume mode became available again.
Cause
The exact fault was not confirmed in this case. The engineers found two likely contributors: the drive motor possibly not registering its lower limit position, and a flat CR2032 backup battery that let stored settings and options lapse — together this explains the single jerk at startup and the ventilator fault.
The cause is probable and was not fully confirmed.
What was done
In this case the plan was to replace the CR2032 backup battery with the machine kept connected to mains power so the settings are not lost, then run the pressure and PEEP calibrations; restoring the options was a procedure from the manufacturer's service documentation, done by authorised personnel. After that, volume mode was expected to be available again — the outcome was reported in the case as probable, not fully confirmed.
Safety
Because the backup battery is changed with the unit connected to mains, keep hands and tools clear of energised parts and complete an electrical safety check before the machine returns to clinical use.
Lesson: A dying backup battery can silently wipe stored settings and options on a ventilator, so check it before chasing motors and sensors.
Covered in the course: Anaesthesia Machine 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.