Low Water/Low Temp

ERROR MESSAGE/ISSUE/SYMPTOMS:

• Low Water and/or Low Temperature

REALTED MODELS:

• 2340EA/EZ9, 2540EA/EZ10, 2540EKA/EZ10K, 3870EA 

WHO CAN SOLVE: 

• User (limited), Technician

CAUSE(S):

• Chamber is overloaded
• Water electrode sensor inside the chamber is dirty
• There is a leak in the system (steam leak or water leak)
• There is a clog in the water line
• Faulty Heating Elements
• Water pump is weak/faulty
• Faulty Temperature Safety Auto Reset
• Pressure reading is too high (stuck solenoid or calibration)

LEVEL OF TROUBLESHOOTING:

USER LEVEL:

• Run a cycle with an unloaded chamber (no instruments) to see if the cycle will complete. If the cycle does complete try another cycle that is loaded with instruments, to test if the chamber is being overloaded. If the unloaded cycle completes but the loaded cycle fails, you may be overloading the chamber and try lessening the load of instruments that is placed inside.
• When the unit is powered off and cool remove the trays and tray holder rack from the chamber. Get a wet rag and wipe off the water electrode inside the chamber (small probe located in back right, rear, bottom of chamber). Afterwards try running another cycle. 
• Look for visible steam leaks near the door as the unit is running (USE CAUTION, STEAM WILL BE HOT).
• When the unit is not running a cycle and the door is open, check the external filter strainer in the back of the unit by unscrewing the metal cap and checking the screen inside the cap, rinse with water to clean if needed. Ensure the cap is screwed back on prior to running another cycle.
• Try adjusting the water inlet time by using the below instructions

Adjusting The Water Fill
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, add an additional 10 seconds to the current WATER IN time
6. After changing it to the desired time press the “STOP” button one more time to exit out of the water fill programming.

7. Try running another cycle and see if the cycle completes.

• If the cycle completes the water pump is most likely weak/faulty or there is a clog in the water line. Get in contact with local service person to schedule a repair.

Technician Level:

Basic troubleshooting

• Ensure all User Level troubleshooting steps above has been 
• Inspect door gasket for any cracks and/or tears
• Check for any clogs in water filter (white plastic filter), the water plumbing lines, and the filter strainer (metal cap at the back of the unit).

img.81- water filters                                                                                                                                     img.81- water filters    

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 the Water Pump and Water Pump Control

Verify that the water pump is functioning by accessing the in/out test. 

1. Power the unit off

2. While the unit is off press and hold the Up-arrow button

3. Continue holding the Up-arrow button and power the unit back on, once the unit beeps twice, let go of the UP and the water pump should be energized, the water pump can be energized twice during the in/out test in case you miss the first selection (img.39). Check to see if you are getting proper line voltage to the water pump (img.40 and img.41).

img.39- in/out test wp

• If the water pump is getting voltage but not running, replace the water pump. The water pump is mounted to the base of the unit between the electronic box and the water reservoir. (img.40)

                                            

img.40- wp

img.41-elec box

• If the water pump is not getting voltage check the fuse in the back of the unit (img.42) to make sure that it hasn't blown, if the fuse is blown, replace it. 

img.42- wp fuse

• If the fuse is not blown check the input voltage connection at the Ajunc3 board (img.43) for the Solid-State Relay (2nd connection from the left of the board).

img.43- wp ssr connect

Checking the SSR

The Water Pump SSR is located in the Electronic Box. Terminals 1 and 2 are on the high voltage side of the SSR that supplies power to the Water Pump. Turn the power off; remove the wires connected to terminals 1 and 2 of the Water Pump SSR. Connect these two wires together and turn the power back on. If the

Water Pump does not run:

• Check that there is power between the wire on terminal 1 and 
  ground.
• Turn the power off and check continuity from the wire on 
  terminal #2, through the Molex connector pin 11 to the Water 
  Pump.
• Check continuity from the return wire on the Water Pump to the return side of the Circuit Breaker.
• If the SSR has power and there is continuity to and from the water pump, the problem is with the pump, and it should be replaced.
• If the pump does run, the problem is with either the Water Pump SSR or the control circuit.
• Check if the Water Pump SSR is being told to turn on. With a DVM read between TP13 and TP1, on the test point board, a 0 to 1 volt DC signal tells the Water Pump SSR to turn on and 10 to 12 volts tells it to turn off. An incorrect signal would indicate a problem with the control 
  circuit.
• If the control signal is correct at the test point, check if the correct signal is at the Water Pump SSR.
• Terminals 3 and 4 are on the control side of the SSR and are connected to JP15 on the Ajunc3 board.
• A reading across terminals 3 and 4 should show 10 to 12 volts DC for the Water Pump SSR to be turned on and 0 to 1 volt if it should be off.
• If the control signal is not correct at the Water Pump SSR, the problem is with the Ajunc3 board, and it should be replaced. After replacing the Ajnuc3 board the new board will need to be recalibrated (see calibration section of this troubleshooting guide).

Checking Exhaust Solenoid for a Leak

• If the water pump 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

Testing the Water Electrode

• If the Water Electrode in the chamber is clean but the unit is still failing, you can test the water electrode to see if it is bad. Power the unit off, press and hold the Up-arrow button, continue holding the Up-arrow button and power the unit on to enter the in/out test. The electrode is the last option in the in/out test (img.50).

img.50- in/out water elect

• With the chamber empty the screen should read 001, put water in the chamber of cover the electrode with a wet paper towel and see if the value changes. 
• If the value does not change, power the unit off and remove the green wire from the water electrode, once disconnected re-enter the in/out test mode. 
• With the water electrode wire disconnected, the display screen should show 001. Ground the wire by touching it against the chassis of the unit and see if the value changes, a ground signal would signify a full chamber of water
• If the value does change when testing performing this test the water electrode is faulty and needs to be replaced. 
• If the value does not change when performing this test, trace the green wire back to where it connects on the Ajunc3 board and test continuity through the wire to ensure the wire isn't the issue.
• If the wire tests ok the Ajunc3 board is faulty and should be replaced, a new Ajunc3 board would need to be recalibrated (see calibration section of this troubleshooting guide).

Pressure Reading is High/Calibration

• Another cause of the low temperature failure or low water failure could be if the pressure reading is too high. If the pressure on the screen ever displays greater than or equal to 34P(psi) the unit will turn off the heating elements. 
• One cause for the pressure reading too high could be if the air outlet solenoid valve is stuck closed, if the air outlet valve is stuck closed the unit will begin to build pressure prior to the temperature reaching 194F (it is programmed to close at 194F normally). 
• Hold the up-arrow button as you power the unit on to enter the in/out test mode and energize the air outlet solenoid (img.51).

img.51- in/out air v

• Once the valve is energized test to make sure the valve is open by touching the valve with a screwdriver and feeling for magnetism. (img.52)

img.52- sol.4

• If the valve is energized but the solenoid is not opening it is a mechanical issue with the valve (stuck plunger or worn valve body) and needs to be replaced. 

• If the valve is not energized remove the screw from the coil and unplug the coil from the wire block, take an ohm reading at the coil to see if the coil is faulty. If the coil is faulty, replace it. (img.53)

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 ohm reading is good, you would need the test point board from the TEST-9 calibration kit to troubleshoot it further. Hook up the test point board and reenter the in/out test and energize the solenoid. Connect your positive lead from your meter to TP14 and connect your negative lead to TP1. 

img.54- valve test.1

img.55- valve test.2

Calibration

• If the Air Outlet Solenoid Valve is not the problem but the pressure reading is still too high causing the failure the issue is most likely calibration. Calibration would require the Tuttnauer TEST-9 calibration kit. 

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

If Pressure Reading is 36P even with the door open

• If the pressure transducer is disconnected from the Ajunc3 board the display would always read 36P and when starting a cycle, the unit will not heat at all. 
• This would never cause a low temperature error, instead it would display low heat, but sometimes it could fail with a low water message. 
• Check the connection from the pressure sensor to the Ajunc3 board to ensure it is connected, if it is already connected try to disconnect and reconnect the Molex connector. If it still reads 36P replace the pressure transducer. 

Testing the Temperature Safety Auto Reset

Note: This is a safety component and should not be replaced until all other possibilities have been ruled out.

If bypassing the safety, never leave the safety bypassed for any reason this method should only be done for testing purposes while watching the unit, the entire time it is running a cycle. Always make sure the unit is unplugged from the wall when connecting the wires, make sure you have a good connection between the wires before plugging the unit back in and powering it on.

• If none of the above troubleshooting has corrected the issue, the problem could be the temperature safety auto reset (img.58).

                                          

img.58- temp safety

• The recommended way to test the temperature safety auto reset is to remove the wires and take an ohm reading to make sure there is resistance or continuity between the terminals, it is best to test this way as quickly as possible after the cycle fails. 
• The temperature safety will reset itself after the unit sits and cools off. If the temperature safety did open and reads O/L or there is not continuity, check the bolts at the top of the chamber (img.59 and img.60) to ensure the heaters are fully tight (loose heating elements could cause the safety to trip) if the heaters were loose, try running another cycle after tightening them.

img.59- new heaters

img.60- old heaters

• The 2nd method is not the recommended way to test the temperature safety, but it would work if the safety were faulty. 
• Power the unit off and unplug the unit from the wall, bypass the temperature safety auto reset and run a test cycle with it bypassed. 
• If the cycle completes and no longer fails, replace the temperature safety auto reset

SOLUTION:

• Load unit properly
• Clean or replace the water electrode
• address the leak
• address the clog
• Replace faulty water pump
• Replace faulty solenoid
• Replace faulty heating element
• Replace faulty temperature safety
• Calibrate unit
• Replace faulty ajunc3 board
• Replace faulty digital predg board