Sterilizer racks dirty?

[pixieduster]

Has anyone ever encountered this: We sterilzed some loaner trays last night and the OR called first thing this a.m. that there were "holes" in the wraps.
We were unable to place towels underneath the trays before wrapping due to an ordering mishap. The undersides of the wrapped trays at some places looked as if they were burned. We resterilized them, towels underneath this time, and again the same problem.

The trays were not heavy, and the autoclave never got above 136 degrees.
We wiped the carriage racks and they did not appear to be dirty or anything.
We cannot figure out the problem. We no longer use the Kim. Clark one step, and did reorder at least one size again. (We thought maybe it was the wrap we are using). Any suggestions?

[barry govenor]

This is a tough one. The only thing I can think of is that there is a remote possibility that your machine's thermostat is malfunctioning and the inside temp may be hotter than is being recorded.

[chipmoore]

Steps to take:
1. Have the burned looking wrap material analyzed to verify discoloration is actually a burn and not a black stain. Is the location of the burn looking material always the same? Top shelf, middle shelf? Where?
2. Locate a lag thermometer that will tell you hottest temperature inside the chamber during the cycle. The temperature you mentioned (136 C) is in the drain and temperatures within the chamber can be much hotter.
3. If the chamber temperature as measured by the lag thermometer show temperatures in excess of the selected temperature (by 12 to 20 deg C), you have superheat conditions, which is dry heat and not good.
4. Make sure the sterilizer is working to Mfg spec and that the steam and water connected are within the Mfg specified range
Chip Moore
Rochester, NY
Retired but involved