High Temperature Fail

 

ERROR MESSAGE/ISSUE/SYMPTOMS:

• High Temperature- message is displayed if the temperature reading reaches 9°F above the set sterilization point. This message will only occur if the unit is reaching the sterilization phase of the cycle and overheating during the set sterilization time

REALTED MODELS:

• All E, EK, EA, EKA, EZ, EZ10K models

WHO CAN SOLVE: 

• End User, Sales Rep- Limited
• Technician

CAUSE(S):

• Chamber is being overloaded
• Chamber pitch not adjusted
• Chamber door is not properly closed
• Sterilization time is set too long
• Water inlet time is nor set properly or needs to be adjusted
• Unit is leaking water from the chamber during the cycle
• Unit is leaking steam from the chamber during the cycle
• Short in heating element(s)
• Short in solid state relay (SSR) for the heating elements
• Calibration
• Faulty PT100 (temperature sensor)
• Ajunc3 board is faulty
• Digital Predg Board is faulty

LEVEL OF TROUBLESHOOTING:

End User Level

• Check the pitch of the chamber to ensure that it is sitting at the correct angle. (img.82, img.83, img.84)

  

  img.82- pitch.1

  

  img.83- pitch.2

  

  img.- 84- pitch.3

• If the water does not reach the front groove of the chamber the unit is sitting too high. If the water starts to spill out of the front the chamber is sitting too low. Adjust the front feet of the unit accordingly.
• Ensure that the door is being closed fully. Continue to close the door even after the door closed light illuminates, typically the door can be closed 1-2 full revolutions after the door closed light illuminates. 
• Ensure that the sterilization time is not set for too long of a time. This can cause the chamber water to boil away causing the unit to overheat. If the sterilization time is set for longer than 10 minutes at a temperature above 250°F (121°C) this could occur. If the sterilization time is needed to be longer than 10 minutes in accordance with an instrument manufacturers IFU the water inlet time will need to be adjusted. 

 

Adjusting the water inlet time

1- With the unit turned on and sitting idle press the “STOP” button (may have to press it multiple times) until your display screen reads “CODE 102”.

2- With “CODE 102” on your screen press the “UP” arrow to change the display to read “CODE 105” (3 presses)

3- With “CODE 105” on the display screen press the “STOP” button one more time.

4- After pressing the “STOP” button again the display screen will show “WATER INLET ###” that number that you will see is the current setting for the water fill at the start of the cycle.

5- Use the “UP” or “DN” arrow to adjust the water fill to the desired time

6- After changing it to the desired time press the “STOP” button one more time to exit out of the water fill programming.

Chamber is overloaded

• Ensure that the unit is not being overloaded, if the unit fails with High Temperature try running the cycle again with 1/2 of your typical instrument load and see if it completes the cycle. If it does complete you may be overloading the chamber. The chambers can only handle so much weight inside the chamber before it will start to have an issue (img.61 and img.62) 

  

  img.61- max load.1

  

  img.62- max load.2

• Inspect the door gasket for any cracks and/or tears, a leaking door gasket can cause the chamber water to boil away causing the unit to overheat. If the door gasket needs to be replaced or is older than 1 year replace the door gasket. 

  Replacing the Door Gasket

• Remove the current door gasket from the door. Begin installing the new door gasket by pressing a section of the gasket into the door at the 12 o'clock position, afterwards press a section into the 6 o'clock position. Then press a section of the gasket into the door at the 3 o'clock position, afterwards press a section into the 9 o'clock position. Continue pressing in the remaining section of the door gasket afterwards. If the gasket is not installed this way, it can stretch causing the door gasket to appear to be too big for the door. 

  

  img.85- door gasket

• If none of the above troubleshooting resolves the issue a technician will be needed to troubleshoot further. 

Technician Level

• Ensure that all user level steps have been completed

Water or steam leak

• Inspect the door gasket for a potential leak, if steam leaks from the door handle area during a cycle or has a whitling noise replace the door bellow.
• Inspect around the solenoid valve fittings, chamber fittings, and top chamber manifold for any signs of a leak. If needed run a cycle with the outer cover off of the unit and look for a leak
• If a leak is found address the leak accordingly, if no leak is found proceed to the next step

Testing the heating elements 

• Unplug the unit and remove the covers
• Remove the insulation blanket from around the chamber 

• Take an ohm reading on the terminals for the heating element, the chart below shows the proper readings. If the readings are incorrect replace the heating elements. (img.15 and img.16)

  

  img.15- ohm and amp

  

  img.16- heaters.1

• Take an ohm reading from the heating elements to ground. If the meter reads O/L there is no short to ground in the heating elements and proceed to the next step. If the meter reads anything other than O/L there is a short to ground in the heating elements and all of the heating elements need to be replaced.  (img.17)

  

  img.17- heaters.2

Testing the Solid State Relay (SSR)

• Unplug the unit and remove the covers

• Label and remove the wiring from the SSR. The SSR for the heating element is located below the ajunc3 board. (img.18 and img.19)

  

  img.18- ssr.1

• SSR with plastic cover removed, terminals 3 & 4- input- 5VDC, terminals 1 & 2- output- Line voltage AC (img.19)

  

  img.19- ssr.2

• Check for a short circuit between terminals 3 & 4, 1 & 2, 3 & 1, 4 & 2, 3 & 2, 4 & 1. Make sure there are no direct shorts. If a direct short is found in the SSR, replace it. If the meter reads O/L proceed to the next step.
• Check for an open between terminals 1 & 2. Be sure to reverse the meter leads and check in the opposite direction. Repeat the procedure for terminals 3 & 4. If an open (O/L) is found, replace the SSR. If the meter does need read O/L, proceed to the next step

• Reconnect the wires to the four connectors of the SSR

  Testing the SSR- terminals 3 and 4

• Ensure that dip switch #4 on the back of the Digital Predg board is off (down position), if the #4 dip switch is on (up) turn it off prior to proceeding (the #4 dip switch is normally off for 120v units and normally on for 230v units). Dip switch #4 is a preheat function, if it is on the heaters will heat once the unit is powered on (img.20). We need the heaters to be off for the next step.

  

  img.20- dip sw

• Plug the unit back in and power it on, ensure that the unit is sitting idle not running a cycle. 
• Take a DC voltage reading from terminal 3 on the SSR to ground, there should be a voltage reading between 3.5v and 5v DC. Afterwards take a DC voltage reading from terminal 4 on the SSR to ground, there should be a voltage reading between 3.5v and 5v DC. A good reading indicates that the SSR is not turned on. 
• If terminal 3 reads properly skip the below testing the power supply section. If terminal 3 does not read between 3.5v and 5v DC, check the power supply to ensure that it is providing the proper voltage. The power supply (circled blue below) is mounted above the ajunc3 board. Unplug the unit and disconnect the output connection from the ajunc3 board (circled white below). (img.21)

Testing the Power Supply

img.21- power supply.1

• Plug the unit back in and power it on, take a DC volt reading between the red and black wires. A good reading is 12v DC. (img.22)

  

  img.22- power supply.2

• Take a DC volt reading between the orange and black wires. A good reading is 5v DC. If the power supply is not reading 5v and 12v DC, replace the power supply. If the readings are correct proceed to the next step to continue testing the SSR. 

  

  img.23- power supply.3

  Testing the SSR- terminals 3 and 4 continued

• If terminal 4 reads correctly skip this next step. If terminal 4 does not read the correct voltage, unplug the unit and remove the wire on terminal 4. Turn the power back on and take a DC voltage reading from terminal 4 on the SSR to ground, there should be a voltage reading between 3.5v and 5v DC. If the reading is still not correct, replace the SSR. If the reading is correct, proceed to the next step

• If the reading is correct, check continuity between the terminal #4 wire and the appropriate connector; unplug the unit when taking this reading. JP4 is the connection for checking the Heater SSR. (img.24 and img.25)

  

  img.24- ssr.3                                                                                                               img.25- ssr.4

• If there is no continuity replace the wiring. If there is continuity and the terminal 4 reading is still incorrect the unit has a control problem, replace the Digital Predg board. 

  Testing the SSR terminals 1 and 2 for 110v units

• Turn the unit on and ensure the dip switch #4 is still off, the heaters must be off for this next step. 
• Terminal 2 of the SSR should read between 110v and 125v AC to ground. Terminal 1 should read near 0 volts AC to ground. Reading across terminals 1 & 2 should show between 110 and 125 volts.
• If terminal 2 does not read between 110 and 125 volts to ground, there is a problem with the line voltage wiring going to the SSR. 
• If terminal 1 shows the same voltage as terminal 2, replace the SSR. If there is a voltage reading less than 100 volts across terminals 1 & 2, replace the SSR.

• Power the unit off so we can enter the in/out test on the unit so we can energize the heaters, this next step must be done with the heaters on. Prior to powering the unit on press and hold the up arrow on the keypad. Continue holding up as you power the unit on. Once the screen comes on release the up button. Press and release the up button to advance to the next step in the in/out test, stop pressing up once the screen displays Heaters. If you accidentally advance past the Heaters option, power the unit off and repeat the steps. 

  In/Out Test menu order

   

  img.26- in/out test

• Terminals 1 and 2 should each read between 110 and 125 volts to ground. If terminal 2 does not show between 110 and 125 volts to ground, there is a problem with the line voltage wiring to the SSR. If terminal 1 does not show between 110 and 125 volts to ground, replace the SSR.
• Reading across terminals 1 and 2 should show close to 0 volts. If the reading across terminals 1 & 2 is greater than 1 or 2 volts, replace the SSR

Testing the SSR terminals 1 and 2 for 230v units

• Turn the unit on and ensure the dip switch #4 is still off, the heaters must be off for this next step. 
• Terminal 1 of the SSR should read between 110v and 125v AC to ground. Terminal 2 of the SSR should read between 110v and 125v AC to ground. If terminals 1 and 2 do not each read approximately 110 volts to ground, there is a problem with the line voltage wiring going to the SSR.
• A reading across terminals 1 & 2 should show between 220 and 235 volts. If a voltage of between 220 and 235 volts is not present across terminals 1 & 2, unplug the unit and remove the wires. 
• Plug the unit back in and carefully take a reading across the wires. If a voltage between 220 and 235 is present across the unconnected wires, the SSR needs to be replaced. If the voltage is still incorrect, the problem is with the line voltage wiring going to the SSR.

• Power the unit off so we can enter the in/out test on the unit so we can energize the heaters, this next step must be done with the heaters on. Prior to powering the unit on press and hold the up arrow on the keypad. Continue holding up as you power the unit on. Once the screen comes on release the up button. Press and release the up button to advance to the next step in the in/out test, stop pressing up once the screen displays Heaters. If you accidentally advance past the Heaters option, power the unit off and repeat the steps. 

  In/Out Test menu order

   

  img.26- in/out test

• Terminal 1 of the SSR should read between 110v and 125v AC to ground. Terminal 2 of the SSR should read between 110v and 125v AC to ground. If terminals 1 and 2 do not each read approximately 110 volts to ground, there is a problem with the line voltage wiring going to the SSR.
• A reading across terminals 1 & 2 should show a voltage near 0 volts AC. If the voltage reading across terminals 1 and 2 is higher than 5 volts, replace the SSR.

• If the SSR tests properly proceed to the next step

Checking Exhaust Solenoid for a Leak

• If the SSR is not the cause of the failures the next most likely cause is the exhaust solenoid valve. If the exhaust solenoid is leaking, you will notice water dripping out from the open end of the copper condensing coil in the water reservoir after the unit starts to build pressure. 
• Either start a cycle and periodically look into the water reservoir (use caution there will be steam and steam will be hot) to see if any water is dripping from the coil or disconnect the coil from the fitting inside the reservoir (img.44) and see if steam and/or water is coming out from the opening (use caution steam will be hot). 

img.44- cc connect

• If you would prefer to inspect the solenoid instead of running a cycle and looking for a leak or notice a leak during the test cycle you should open the solenoid valve (when the unit is powered off and no pressure is in the chamber) and look for any debris and/or cracks in the seat of the valve. 
• Also inspect the solenoid plunger for tears. 
• The exhaust solenoid valve will be mounted to the base of the unit and be connected to a copper plumbing line that elbows up from it and connects to the water reservoir (solenoid to the condensing coil). 
• On any 2340EA/EZ9 or 2540EA/EZ10 it will be the rear most solenoid valve on the base in the unit (img.45), on a 3870EA it would be the front most solenoid on the base in the unit (img.46). 

                                                   2340EA/EZ9 and 2540EA/EZ10

img.45- sol9/10

                                                              3870EA

img.46- sol38

img.47- sol.1

img.48- sol.2

If the solenoid is dirty or has debris clean it and try running another cycle. If the valve continues to leak or the valve is cracked, and/or no debris is found replace the solenoid.

Air Outlet Solenoid Valve

If the exhaust solenoid is good, check the air outlet solenoid (may not be labeled with 41 like in the photo below) on the back of the reservoir (img.49) for cracks and/or debris as well by opening the solenoid valve. If the air outlet solenoid is leaking it would be leaking steam back into the water reservoir tank from where the solenoid connects and it would be very difficult to see by looking into the water reservoir with the unit running. 

img.49- sol.3

• If the solenoid is dirty or has debris clean it and try running another cycle. If the valve continues to leak or the valve is cracked, and/or no debris is found replace the solenoid.
• If neither the solenoid valves are not having a mechanical issue, proceed to the next step 

Solenoid Valve Electrical Issue- Valve always energized

• Power the unit on but do not start a cycle
• Locate the exhaust solenoid valve or the air outlet valve (both valves should be checked, it does not matter which one is checked first)
• Air valve- should be energized sitting idle when the door is closed, should not be energized when sitting idle and the door is open. Open the door and feel for magnetism at the coil. If the coil is energized continue with troubleshooting the electrical solenoid valve issue. If the coil is not energized with the door open proceed to the next section of troubleshooting (calibration issue).

• Exhaust solenoid valve- check to see if there is magnetism to the coil when the unit is not running. Sitting idle there should be no magnetism. If the coil is energized continue with troubleshooting the electrical solenoid valve issue. If the coil is not energized with the door open proceed to the next section of troubleshooting (calibration issue).

  Note: Solenoid valve in picture below is the air outlet valve. The exhaust solenoid valve should be checked in the same area of the valve (near the nut) but on the exhaust valve

  

  img.52- sol.4

• If either solenoid is energized when it shouldn't be, unplug the unit and remove the solenoid valve coil from the plunger, remove the Phillips head screw from the coil and unplug the coil from the wire harness. Once the coil is unplugged take an ohm reading at the coil to ensure there is no short in the coil. 

  Note: The coil will either be 12vdc 10w or 12vdc 12w, the ohm reading would be different between the two coils, the coil would be labeled.

  

img.53- sol.5

• If the solenoid coil(s) read correctly check the wiring at the back of the ajunc3 board (12 pin connection for exhaust valve. 4 pin connection with only 2 wires- sits directly above the 12 pin- for the air outlet valve) ensure that the wiring is intact, has a good connection, and no corrosion is found. Address any wiring issue if needed, if the wiring is not causing the issue, reconnect the connector and proceed to the next step.

  

  img.6- ajunc3 12 pin.1

• If the valve(s) still remain open when they should be closed replace the Digital Predg board

  Calibration issue

• If the unit needs to be calibrated it can cause the unit to fail for High Temperature. Either the pressure reading could be reading low, or the temperature reading could be high. The calibration should not be checked until it is verified that there is no water or steam leak from the chamber. 

• Disconnect the copper line from the top rear chamber manifold that connects to the pressure transducer

  

  img.27- pressure test.1

• Connect a pressure gauge in its place and reconnect the copper line from the pressure transducer to the pressure gauge

  

img.28- pressure test.2

• Run a test cycle and verify that the pressure reading from the display screen matches the pressure gauge reading. If the pressure readings do not match, proceed to the calibration instructions. If both pressure readings match the issue is not the pressure transducer or the calibration and proceed to the next section

  Calibration

  

  img.29- cal.1

  

  img.30- cal.2

  

  img.31- cal.3

  

  img.32- cal.4

  

  img.33- cal.5

  

  img.34- cal.6

  

  img.35- cal.7

  

  img.36- cal.8

  

  img.37- cal.9

  

  img.38- cal.10

• If only the pot 2 adjustment cannot be made replace the pressure transducer. If the issue persists with a new pressure transducer replace the ajunc3 board. 
• If pot 4 and/or pot 5 cannot be calibrated to the proper range replace the ajunc3 board. 

• If the calibration adjustment is done without issue but the temperature still reads high on the display screen and fails for high temperature, we need to enter the in/out test to determine if the issue is the temp sensor or the Digital Predg board. 

   

   

   

   

   

   

   

   

   

  Testing PT100/Display screen accuracy after calibration

• Power the unit off and connect the PT100 simulator box (if it is disconnected) to the back of the ajunc3 board as if you were performing a calibration. (img.56 and img.57)

  

  img.56- pt test.1

  

  img.57- pt test.2

• Prior to powering the unit on press and hold the up arrow on the keypad. Continue holding up as you power the unit on. Once the screen comes on release the up button, the unit will now be in the in/out test. Press and release the up button to advance to the next step in the in/out test, stop pressing up once the screen displays PT100. If you accidentally advance past the PT100 option, power the unit off and repeat these steps. 

  In/Out Test menu order

  

  img.26- in/out test

• Check the temperature reading the display screen shows against each temperature setting of the PT100 simulator. 
• If the reading is matches or is within 1-3°F replace the temperature sensor. 
• If there is a large difference between the PT100 simulator setting and the display screen value replace the Digital Predg board

PT100 (Temperature sensor) issue

• The PT100 having an issue is less likely but can cause the unit to high temp fail. 
• The temperature on the display screen should only change by 1-2°F throughout the cycle. If you notice the display screen temperature is jumping up or down in temperature by a large range of temperature replace the temperature sensor
• Allow the unit to cool down to room temperature, disconnect the temperature sensor from the back of the ajunc3 board. Take an ohm reading on the wires from the temp sensor, at room temperature the PT100 should read about 110Ω. If the reading is incorrect replace the PT100

img.86- pt100

Least likely PT100 (temperature sensor) issue 

• If the unit fills the chamber with water and immediately fails for high temperature either the temperature sensor is disconnected from the back of the ajunc3 board, or the connection is poor and needs to be addressed. 

SOLUTION:

• Load chamber properly
• Adjust chamber pitch
• Close chamber door properly 
• Reduce sterilization time
• Adjust water inlet time
• Replace faulty door gasket
• Replace faulty door bellow
• Address other steam or water leak
• Replace faulty heating element(s)
• Replace faulty solid state relay (SSR) for the heating elements
• Perform calibration
• Replace faulty PT100 (temperature sensor)
• Replace faulty ajunc3 board
• Replace faulty Digital Predg Board