YouJoy BES12: steam temperature stalls low, sterilization cycle aborts
What happened
Reported in the case: in sterilization mode the temperature stopped at 104 °C at 0.2 atm and the cycle ended with error E9 — the unit never reached sterilization conditions.
What was checked
- The engineers worked through the water feed path from the clean tank to the pump: filter, inlet valve and the steam generator temperature sensor.
- The engineers found the filter in the clean-water tank, on the line feeding the pump, heavily clogged and restricting water flow to the steam generator.
Cause
In this case the likely cause was a clogged filter in the clean-water tank on the pump feed line: too little water reached the steam generator, so it could not build the steam pressure and temperature needed for sterilization. The cause is considered probable, not yet fully confirmed.
The cause is probable and was not fully confirmed.
What was done
The filter was removed, cleaned and washed. After reassembly the temperature started rising again, but the 134/2.1 cycle (as reported in the case) still fell slightly short of setpoint, so the engineers kept the unit under observation; the fix is considered probable but not yet fully confirmed.
Safety
Before opening the water circuit, isolate the sterilizer from the mains, let the steam generator and lines cool and relieve the pressure — hot water and steam under pressure can cause severe burns; run an electrical safety test before returning the unit to use.
Lesson: When an autoclave stalls below sterilization temperature, work through the water feed path (tank filter, pump, valves) before suspecting sensors or control — a starved steam generator cannot build pressure.
Covered in the course: Steriliser 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.