High Pressure Fail

 

ERROR MESSAGE/ISSUE/SYMPTOMS:

• High Pressure Fail- This issue occurs if the pressure reading reaches above the maximum allowed pressure parameter during a cycle (10 PSI above the sterilization pressure) 

REALTED MODELS:

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

WHO CAN SOLVE: 

• End User or Sales Rep- Limited

• Technician

CAUSE(S):

• Sterilization temperature is set too high
• Short in heating element(s)
• Short in solid state relay (SSR) for the heating elements
• Other short circuit
• Calibration
• Pressure Transducer is Faulty
• Ajunc3 board is faulty
• Digital Predg Board is faulty

LEVEL OF TROUBLESHOOTING:

End User Level

• Lower the set sterilization temperature, if this resolves the issue the set temperature may be too high. The sterilization temperature should never be set above 273°F (134°C). If this does not resolve the issue you will need a technician to troubleshoot further

Technician Level

• Ensure all user level troubleshooting has been completed

 

 

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

Testing the Pressure

• Disconnect the copper line from the top rear chamber manifold that connects to the pressure transducer (img.27)

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)

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 (img.29 - img.38). 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 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 the calibration voltage reading for pot 2 is correct but the display screen pressure reading is still inaccurate from the pressure gauge replace the Digital Predg board

• If all of the above steps still do not resolve the High Pressure failure, one by one inspect each wire inside the unit for a potential short to ground. This is very uncommon, a short would typically cause the circuit breaker to trip, not a high pressure failure

SOLUTION:

• Adjust sterilization set time properly
• Replace the faulty heating elements
• Replace the faulty Solid State Relay (SSR) for the heating elements
• Address wiring or connection issue
• Calibrate the unit
• Replace the faulty pressure transducer
• Replace the faulty ajunc3 board
• Replace the faulty Digital Predg board