Just received an email with a Midmark M11 Autoclave Repair question. I get so excited when someone asks for our help.
It gives me the opportunity to work with someone new, and allows me the luxury of examining a problem from someone else’s perspective…..forcing me to look at it in a different way.
Here is the email I received:
I have a Midmark M11 Ultraclave and after our monthly cleaning we keep getting error code 1. We have done everything recommended in our trouble shooting manual. Don’t want a costly repair can you help?
The Problem: Midmark M11 Displaying Error Code E001
In most cases, we are simply told about the Error E001 without any additional detail. Which is fine. And we respond with a laundry list of things that could be causing the problem and start the troubleshooting process.
But in this case, they told us it started happening right after they cleaned it. With the extra detail in this email, we can hone in on the problem with the Midmark M11 Autoclave pretty quickly.
The Cause: The Midmark M11 Water Level Sensor
You can find the water level sensor by Clicking Here
We immediately suspected the Water Level Sensor was causing the problem.

And here is what we think happened: When wiping everything down, the water level sensor in the back of the chamber got wet, and remained that way.
The Midmark M11 Water Level Sensor has 1 wire going to it, and it is a hot wire. In order for a circuit to be complete, you also have to have a ground. When water touches the end of the sensor, it completes the circuit and sends the message back to the PC board that there is sufficient water in the chamber to start the sterilization process.
If the sensor is wet when the cycle is started, the circuit is complete as far as the PC Control Board is concerned and it will skip the fill process and immediately go into the startup phase (heat).
Without any water in the chamber, it will overheat pretty quickly causing the overheat thermostat to cut the power to the heating element, and trigger the E001 error code
Is it Really The Problem?
Verifying the problem could not be easier. Simply start the cycle and watch your display. If it bypasses the Filling process (ie: The LCD Display should say Filling”) and goes straight to the heat up mode instead…..then the Water level Sensor is causing the problem.
In this case, we were told the Midmark M11 autoclave was skipping the filling cycle
And the cure in this case was to simply remove the base tray and cage to get to the sensor, and then dry the sensor with a cloth

As a foot note, had drying the sensor not cured the problem, then the next step would have been to test the Water Level Sensor. You can find the test by clicking here.
They were able to successfully complete the autoclave repair on their Midmark M11, and it did not cost them a dime!