FDI P2131, Technical Manual, Page: 12 / 161

2.4 Description of Cycle Phases
Schematic of a Dynamic Air Removal (Pre ‐ Vac) Cycle
Below is a description of the various phases of a P2131 sterilizer textile or wrapped instrument
cycle. NOTE: The IUSS cycle has no dry phase.
1. Preconditioning (pre ‐ vacuum)
a. Steam Flush – An initial pulse of steam is released into the chamber and flows
directly out of the chamber into the WRS. This steam flush removes most of the
air from the chamber.
b. Vacuum Pulse #1 – A medium vacuum is pulled on the chamber to remove more
air.
c. Steam Pulse #1 – Steam is released into the chamber to increase pressure and
temperature to heat up the load.
d. Vacuum Pulse #2 – A slightly deeper vacuum is pulled on the chamber to remove
even more air.
e. Steam Pulse #2 – Steam is released into the chamber again to increase pressure
and to continue heating up the load.
f. Vacuum Pulse #3 – This is the final and deepest vacuum pulse during which nearly
all of the air is removed from the chamber.
2. Heatup – During this phase, steam fills the chamber to build up pressure and temperature
until the exposure temperature is reached.
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