Door Unlock Fail – Tuttnauer

ERROR MESSAGE/ISSUE/SYMPTOMS:

Door Unlock- this message occurs if the door opens during a cycle or if the door switch becomes open during a cycle.

REALTED MODELS:

All E, EK, EA, EKA, EZ, EZ10K Models

WHO CAN SOLVE:

End User or Sales Rep- limited
Technician

CAUSE(S):

Door is not fully closed prior to starting a cycle
Door switch activator screw is too tight, missing parts, or missing entirely
Door Switch is faulty
Closing Device is worn
Wiring or connection issue
Ajunc3 board is faulty
Digital Predg board is faulty

LEVEL OF TROUBLESHOOTING:

End User/Saler Rep level

Ensure that the door is fully tightened before starting a cycle. Continue to close the door even after the door closed signal light illuminates 1-2 more full revolutions.
Check to make sure the door switch activator screw is installed correctly. The door switch activator screw is circled below in yellow it is the top right screw (inside of the door), it should be longer than the other 3 screws and have 2 washers and a spring. Try loosening the screw so it sticks out more, this will make the door switch be pushed in further and may resolve the issue. (img.10)

img.10- door sw act

If the unit still fails for door unlock a technician will be needed

Technician Level

Ensure all user level troubleshooting has been completed
Unplug the remove the covers
Inspect the closing device on the unit to ensure that it is in a good condition (img.11). Listen for any grinding noise or squeaking noise when turning the handles. Look for evidence of metal shavings near the bottom of the unit, door cover, and on the closing device. Ensure that all 4 washers and bearings are intact near the rear of the closing device. If the closing device is worn, the pressure inside the chamber can push the door out slightly causing the door switch activator screw to lose contact with the door switch and fail the cycle for door unlock. If the closing device is worn or damaged replace the closing device. The closing device should be oiled with a light machine oil on a monthly basis to prevent it from becoming worn or damaged. If the closing device is not causing the issue, proceed to the next step.
***Important note regarding the closing device***
If the closing device is worn or damaged and is determined to be causing the issue, this is a major safety concern. The unit should not be used for any reason until the closing device is replaced with a new one. Running the autoclave with a worn or damaged closing device can cause the door to fully open during a cycle and can cause serious bodily injury or death to anyone near the autoclave
img.11- closing device
Locate the door switch and ensure the green wire is connected to the common terminal and the ground wire is connected to the normally open terminal. (img.12 and img.13)
img.12- door sw.1

img.13- door sw.2
Disconnect the wiring from the door switch and ensure that the wiring is intact
Test continuity between the common and normally open terminal. There should be no continuity when the door is open. Close the door or press the door switch with your finger to see if there is continuity when the door is closed. If there is no continuity when the switch is pressed/door is closed, replace the door switch (img.14). If the door switch is not causing the issue, proceed to the next step
img.14- door sw.3
Check the door switch connection at the back of the ajunc3 board (12-pin connector) to ensure that the wiring is intact, has a good connection, and no corrosion is found. Address any wiring issue if needed (img.6 and img.7), if the wiring is not causing the issue, reconnect the connector and proceed to the next step.
img.6- ajunc3 12 pin.1

img.7- ajunc3 12 pin.2
Inside the electronic box there is a grey ribbon cable that connects the Digital Predg board w/ keypad to the ajunc3 board. Disconnect both end of the ribbon cable and reverse them (take the end that was in Digital Predg board and plug into the ajunc3 board and vice versa). The ribbon cable is keyed so it will only plug in one way
img.8- ribbon cable 1

img.9- ribbon cable 2
Ensure that the ribbon cable connection is good after reversing the connection, the arms on the connectors of the boards should snap into place. Plug the unit back in but do not power the unit on, perform a factory reset on the unit.
Factory Reset Procedure
1- With the unit powered off press and hold the "STOP" button on the keypad
2- As you are holding the "STOP" button power the unit on and continue holding "STOP"
3- When you power the unit on it will beep one time, do not let go of "STOP" until the unit beeps two additional times
4- After letting go of the "STOP" button the factory reset is complete
After reversing the ribbon cable and performing the factory reset, try running another cycle. If the unit no longer fails for Door Unlock the issue was resolved, either by the software or by the ribbon cable. It is recommended to replace the ribbon cable. If the unit continues to fail proceed to the next step
If the unit still fails replace the ajunc3 board and perform the calibration on the new board
If after replacing the ajunc3 board the unit continues to fail, replace the digital Predg board (this is very uncommon to cause the issue and should only be done if no other attempts resolve the issue)