Autoclaves · E Series family

Tuttnauer EA2540: troubleshooting and error codes

The ServiceForge knowledge base holds 111 documented symptoms for the Tuttnauer EA2540, with 340 ranked causes, 310 diagnostic checks with test points and expected values, and 14 error codes. Each symptom below shows its causes and the first check; the rest is one connection away. Connect ServiceForge to your AI

Symptoms

Instruments or packs are damp or wet

Sterilized items retain moisture after drying cycle completion

Ranked causes

1. Drying cycle not available for liquid cycles (common)
2. Drying time too short (common)
3. Autoclave overloaded (common)
4. Low wall outlet voltage (occasional)
5. Safety Thermostat interrupting drying cycle (occasional)
6. Air Outlet Valve clogged or inoperative (occasional)
7. Exhaust Valve clogged or inoperative (occasional)
8. Chamber Strainer clogged (occasional)
9. Water reservoir overfilled (occasional)
10. Pinhole in Cooling Coil body (E/EK only) (rare)
11. Cooling Coil open end submerged in reservoir (E/EK only) (occasional)
12. Defective Check Valve (EA/EKA/EZ/EZ10k) (occasional)
13. HEPA Filter dirty or clogged (EA/EKA/EZ/EZ10k) (common)
14. Dry Pump not operating or weak (EA/EKA/EZ/EZ10k) (occasional)
15. Dry Solenoid not opening (EA/EKA/EZ/EZ10k) (occasional)
16. Fill Tube or Chamber Screen clogged (EA/EKA/EZ/EZ10k) (occasional)

16 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Chamber does not fill with water

Water does not enter the chamber during fill cycle

Ranked causes

1. Reservoir not filled with distilled water to proper level (common)
2. Pickup tube blocked at bottom of reservoir (common)
3. Water Sensor dirty or contaminated (common)
4. Water Sensor shorted or defective (occasional)
5. Clogged filter screen (pre-9/96 models) (occasional)
6. Clogged chamber strainer (9/96-2/2000 models) (occasional)
7. Clogged chamber strainer (post-2/2000 models) (occasional)
8. Clogged pump strainer (microprocessor T97DN7WP or later) (occasional)
9. Water pump malfunction (microprocessor T97DN7WP or later) (occasional)
10. Clogged water filter in reservoir (occasional)
11. Clog at water fill valve (occasional)
12. Deformed seat on water fill valve plunger (occasional)
13. Clog in water fill line (occasional)

First check

Verify reservoir water level

Test point: Reservoir
Expected: Filled with distilled water to just below Pressure Relief Valve

4 more checks with pass and fail actions, 14 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Circuit breaker or fuse gets hot high voltage

Circuit breaker or fuse becomes excessively hot during operation

Ranked causes

1. Incorrect input voltage (common)
2. Bad plug on Line Cord (occasional)
3. Faulty wall receptacle or autoclave receptacle (occasional)
4. Loose wire connections causing arcing (common)
5. Excessive amperage draw from faulty Heating Elements (common)
6. Loose internal connections in Fuse Holder (occasional)
7. Circuit Breaker weakened over time (occasional)

First check

Measure voltage at wall outlet

Test point: Wall outlet
Expected: 110-125V for 110V units; 220-235V for 220V units, ±15V for 110V units; ±15V for 220V units
Tools: DMM

5 more checks with pass and fail actions, 7 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Circuit breaker or fuse has no output high voltage

No power output from main circuit breaker or fuse on equipment

Ranked causes

1. Low or incorrect input voltage at wall outlet (common)
2. Bad Line Cord (common)
3. Faulty power receptacle at autoclave back panel (occasional)
4. Blown fuse (fused units only) (common)
5. Faulty Fuse Holder (fused units only) (occasional)
6. Circuit Breaker not in on position (circuit breaker units only) (common)
7. Faulty Circuit Breaker (circuit breaker units only) (occasional)

First check

Measure voltage at wall outlet

Test point: Wall outlet
Expected: 110-125V for 110V units; 220-235V for 220V units, ±15V for 110V units; ±15V for 220V units
Tools: DMM

9 more checks with pass and fail actions, 7 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Cut-Out Thermostat reset button trips continuously caution

Reset button keeps activating repeatedly during operation

Ranked causes

1. Incorrect unit voltage (common)
2. Water Sensor dirty or obstructed (occasional)
3. Incorrect water fill level (occasional)
4. Cut-Out Thermostat installed incorrectly (occasional)
5. Water or steam leak in autoclave (occasional)
6. Temperature setting exceeds 273°F (134°C) (common)
7. Cut-Out Thermostat faulty (rare)

7 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Dry Pump does not turn on

Pump motor fails to activate during dry cycle or remains off throughout dry cycle

Ranked causes

1. Dry Pump Fuse blown (common)
2. Pinched wire or open in power leads to Dry Pump (occasional)
3. Dry SSR (Solid State Relay) failed (occasional)
4. Dry Pump motor failed (occasional)
5. Dry SSR not receiving correct control signal from microprocessor (occasional)
6. Dry SSR not receiving signal at relay terminals (occasional)
7. Ajunc board failed (signal not reaching Dry SSR) (occasional)

First check

Test Dry Pump Fuse for continuity

Test point: Dry Pump Fuse (located above main voltage fuses/breaker)
Expected: Continuity present (< 1 ohm)
Tools: Ohmmeter

4 more checks with pass and fail actions, 7 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Water leaking from under autoclave caution

Water pools or drips from beneath the unit during operation or standby

Ranked causes

1. Loose or broken fittings (common)
2. Water reservoir crack or hole (occasional)
3. Leak in chamber indicated by rust on heating elements (occasional)
4. Cooling coil exit spout pointed toward reservoir (occasional)
5. Reservoir gasket missing or damaged (occasional)
6. Reservoir overfilled (common)
7. Rinse water from cleaning spilled into autoclave (occasional)

First check

Inspect fittings for leaks

Test point: All fittings under autoclave
Expected: Tight, no water leakage

5 more checks with pass and fail actions, 7 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Add Water Indicator always on

Add Water light remains lit continuously regardless of actual water level

Ranked causes

1. Float Switch stuck or not moving freely (common)
2. Loose or broken connector at JP2 on Ajunc board (common)
3. Incorrect voltage reading at TP8 or TP1 (occasional)
4. Faulty Digital Predg board or Flat Cable (occasional)
5. Faulty Float Switch (occasional)
6. Control Problem on circuit boards (rare)

First check

Verify Float Switch moves freely

Test point: Float Switch mechanism
Expected: Switch moves freely up and down

4 more checks with pass and fail actions, 7 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Air outlet valve stays closed all the time

Air outlet valve remains closed and does not open during sterilization cycle

Ranked causes

1. Control signal problem indicating valve should stay closed (occasional)
2. Broken wire to solenoid coil (occasional)
3. Solenoid coil short or open (occasional)
4. Connection box connectors loose or not making contact (occasional)
5. Plunger assembly stuck or not moving (occasional)
6. Plunger housing deformed causing binding (occasional)

First check

Test air outlet valve control voltage

Test point: TP14 to TP1
Expected: 0-1 volt DC when valve should open V, 0-1 V
Tools: DVM

5 more checks with pass and fail actions, 6 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Low heat - temperature not reached

LOW HEAT message displayed, Cycle Fail indicator lights, cycle aborts if autoclave fails to reach sterilization temperature after heating for 50 minutes (Wrapped/Unwrapped) or 80 minutes (Liquid program)

Ranked causes

1. No power to Heating Elements (common)
2. Bad Heating Elements (common)
3. Very low line voltage delaying heat up (occasional)
4. Safety Thermostat opening prematurely (occasional)
5. Clogged Air Jet (occasional)
6. Air Outlet Valve stuck closed (occasional)

Low pressure during sterilization

LOW PRES message displayed, Cycle Fail indicator lights, cycle aborts if pressure drops 4 PSI (0.27 BAR) below required sterilization pressure

Ranked causes

1. Insufficient water in chamber (common)
2. Heating Elements not cycling on/off properly - Solid State Relay problem (common)
3. Heating Elements not cycling on/off properly - control circuit problem (common)
4. Bad Heating Elements not producing enough wattage (occasional)
5. Safety Thermostat opening prematurely (occasional)
6. Bad Pressure Transducer (rare)

Power supply input voltage absent or incorrect high voltage

Input wires to power supply have no voltage or incorrect voltage level

Ranked causes

1. Broken or loose On/Off switch (occasional)
2. Loose or disconnected Molex connector on electronic box (occasional)
3. Loose wires in Molex connector (occasional)
4. Open Cut-Out thermostat (occasional)
5. Circuit breaker or fuse tripped (occasional)
6. Damaged power cord (occasional)

First check

Turn power off and disconnect power supply output wires from JP3 connector

Test point: JP3 connector on Ajunc board
Expected: Wires removed

3 more checks with pass and fail actions, 7 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Steam leaking from chamber caution

Steam visible or audible escaping from chamber during sterilization cycle

Ranked causes

1. Door gasket cracked or worn (common)
2. Door bellows leaking or damaged (occasional)
3. Door not closing properly or not sealing chamber (common)
4. Loose fittings on plumbing connected to chamber (occasional)
5. Leak in chamber indicated by rust on heating elements (occasional)
6. Debris in solenoid valves causing plunger to stick (occasional)

First check

Inspect door gasket condition

Test point: Door gasket
Expected: No cracks, tears, or visible wear

3 more checks with pass and fail actions, 6 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Water leaking back into chamber caution

Water flows from reservoir back into chamber during drying cycle or cool down

Ranked causes

1. Reservoir overfilled (common)
2. Cooling coil exit below water line (E and EK machines) (occasional)
3. Perforation in cooling coil below water line (E and EK machines) (occasional)
4. Check valve failure (EA, EKA, EZ, EZ10k machines) (occasional)
5. Fill valve leaking or not closing fully (occasional)
6. Debris or deformation in fill valve plunger preventing closure (occasional)

First check

Verify reservoir fill level

Test point: Reservoir
Expected: Filled only to base of Safety Valve Holder

4 more checks with pass and fail actions, 7 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Add Water Indicator always off

Add Water light remains off continuously even when water level is low

Ranked causes

1. Float Switch stuck or not moving freely (common)
2. Loose or broken connector at JP2 on Ajunc board (common)
3. Wires to Float Switch shorted to chassis (common)
4. Incorrect voltage reading at TP8 or TP1 (occasional)
5. Faulty Digital Predg board or Flat Cable (occasional)

First check

Verify Float Switch moves freely

Test point: Float Switch mechanism
Expected: Switch moves freely up and down

4 more checks with pass and fail actions, 6 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Air outlet valve blows off during sterilization cycle caution

Air outlet valve opens or ejects forcefully during sterilization cycle when pressure should be rising

Ranked causes

1. Temperature setting too high (above 273°F/134°C) (common)
2. Heating elements not operating properly (common)
3. Heating elements installed improperly (occasional)
4. Pressure sensor miscalibrated (occasional)
5. Temperature sensor miscalibrated (occasional)

First check

Verify temperature setting

Test point: Control panel temperature setting
Expected: 273°F (134°C) or lower

4 more checks with pass and fail actions, 5 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Air outlet valve stays open all the time

Air outlet valve remains open and does not close during sterilization cycle

Ranked causes

1. Control signal problem indicating valve should stay open (occasional)
2. Ground short in black wire from solenoid to electronic box (occasional)
3. Solenoid coil short or open (occasional)
4. Plunger assembly stuck due to debris (occasional)
5. Plunger housing nicked or distorted preventing movement (occasional)

First check

Test air outlet valve control voltage

Test point: TP14 to TP1
Expected: 3.5-5 volts DC (valve off) or 0-1 volt DC (valve on) V, 3.5-5 V or 0-1 V
Tools: DVM

4 more checks with pass and fail actions, 5 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Circuit breaker or fuse trips immediately upon plugging in unit high voltage

Circuit breaker or fuse opens the moment the power plug is inserted, even with main switch off

Ranked causes

1. Main switch is on when unit is plugged in (common)
2. Faulty Fuse Holder or Circuit Breaker (occasional)
3. Ground short at Heating Elements (common)
4. Thermostat capillary tubes shorting autoclave receptacle (rare)
5. Damaged or shorted wires in unit (occasional)

First check

Verify main switch is off before plugging in unit

Test point: Main power switch position
Expected: Switch in off position

5 more checks with pass and fail actions, 5 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Cut-Out Thermostat does not shut off power to autoclave high voltage

Autoclave continues to heat beyond normal shutdown point, thermostat not cutting power

Ranked causes

1. Sensing probe installed in wrong heating element channel (common)
2. Sensing probe does not have tight fit (common)
3. Tubing kinked at probe connection (occasional)
4. Heating element ground short (occasional)
5. Cut-Out Thermostat faulty (rare)

5 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Display flickers

Display screen flickers or flashes intermittently

Ranked causes

1. Incorrect +5V supply to display (common)
2. Display contrast improperly adjusted (occasional)
3. Defective backup battery or real-time clock (occasional)
4. Defective microprocessor (occasional)
5. Defective Digital Predg board (occasional)

First check

Measure display power supply voltage

Test point: TP17 to TP1
Expected: +5 volts DC V

5 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Door Switch indicator always off

Door closed indicator light remains dark when door is closed

Ranked causes

1. Door Switch stuck or sticking (common)
2. Door Switch Activator misadjusted or missing (common)
3. Door not closing tight enough (occasional)
4. Poor ground connection on Door Switch (occasional)
5. Digital Predg board or Flat Cable failure (rare)

First check

Verify Door Switch moves freely

Test point: Door Switch
Expected: Moves smoothly in and out

5 more checks with pass and fail actions, 6 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Dry pump does not pump air

Pump runs but no air flow from pump outlet

Ranked causes

1. HEPA filter clogged (common)
2. Dry Solenoid not activated (common)
3. Dry Solenoid plunger stuck or defective (occasional)
4. Blockage in tubing from valve base to chamber (occasional)
5. Blockage in tubing or failed pump (occasional)

First check

Verify HEPA filter condition

Test point: HEPA Filter inlet
Expected: Filter not clogged; air flows freely

5 more checks with pass and fail actions, 5 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Items are burning or melting patient safety

Sterilized items show burn marks, melting, or heat damage after cycle

Ranked causes

1. High wall outlet voltage (common)
2. Items contacting hot chamber wall (common)
3. Heating Elements shorted (occasional)
4. Heat SSR defective (occasional)
5. Safety or Cut-Out Thermostat malfunction (occasional)

5 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Printer does not print

Printer is unresponsive or produces no output during normal operation

Ranked causes

1. No paper in printer or paper not installed correctly (common)
2. Printer cable disconnected or loose (common)
3. Dip switch 8 not set to up position (common)
4. Faulty printer cable or Digital Predg board (occasional)
5. Printer hardware failure (occasional)

First check

Verify paper is loaded and thermal type

Test point: Printer paper tray
Expected: Paper loaded, thermal paper confirmed, no scraps in head

3 more checks with pass and fail actions, 5 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Safety Thermostat does not turn off heaters during Dry Cycle caution

Heaters remain on during Dry Cycle when Safety Thermostat should terminate heating phase

Ranked causes

1. Sensing probe improperly installed or loose (common)
2. Sensing probe tubing kinked or restricted (occasional)
3. Safety Thermostat is hard-wired and has failed (early control proms T93N3 or earlier) (occasional)
4. Heat SSR failure or ground short in Heating Elements or control problem (rare)
5. Safety Thermostat microprocessor connection failed (T93N3 or later) (rare)

First check

Verify sensing probe installation location

Test point: Rear-most Heating Element lower channel
Expected: Probe seated in lower channel

5 more checks with pass and fail actions, 5 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Water Pump does not pump water caution

Pump energizes but delivers no water flow to chamber

Ranked causes

1. Pump Strainer clogged (common)
2. Fill Solenoid not activating (occasional)
3. Fill Solenoid plunger stuck or faulty (occasional)
4. Tubing blockage from valve to chamber (occasional)
5. Tubing blockage from pump to valve or water pump faulty (occasional)

First check

Inspect Pump Strainer for debris or clogging

Test point: Pump Strainer
Expected: Strainer clean with no visible blockage

5 more checks with pass and fail actions, 5 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Water Pump does not turn on

Pump not operating when power applied, no motor activity

Ranked causes

1. Water Pump Fuse blown (common)
2. Pinched or open wire in pump power leads (common)
3. Water Pump SSR faulty or control circuit problem (occasional)
4. Water Pump faulty (occasional)
5. Ajunc board faulty or incorrect control signal (rare)

First check

Test Water Pump Fuse continuity

Test point: Water Pump Fuse
Expected: Continuity present (fuse good)
Tools: Ohm meter

4 more checks with pass and fail actions, 5 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Air outlet opens at wrong time

Air Outlet Valve opens or closes at incorrect times during cycle

Ranked causes

1. Defective LM34 temperature sensor (common)
2. Shorted black wire to solenoid coil (occasional)
3. Defective solenoid coil (occasional)
4. Loose or poor solenoid coil connector contact (occasional)

First check

Measure signal voltage at temperature sensor output

Test point: TP14 to TP1
Expected: 0 to 1 volt DC if valve should be open, 3.5 to 5 volts DC if valve should be closed V

5 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Display shows no characters

Display is powered on but no text or characters are visible on screen

Ranked causes

1. Incorrect +5V supply to display (common)
2. Display contrast improperly adjusted (common)
3. Defective microprocessor (occasional)
4. Damaged LCD display (occasional)

First check

Measure display power supply voltage

Test point: TP17 to TP1
Expected: +5 volts DC V

4 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Display shows wrong characters

Display is showing incorrect characters or garbled text

Ranked causes

1. Incorrect +5V supply to display (common)
2. Defective backup battery or real-time clock (occasional)
3. Defective microprocessor (occasional)
4. Defective Digital Predg board (occasional)

First check

Measure display power supply voltage

Test point: TP17 to TP1
Expected: +5 volts DC V

4 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Dry pump blows fuse caution

Fuse in dry pump circuit repeatedly opens under load

Ranked causes

1. Dry pump fan blade stuck (common)
2. Pinched wire or ground short in power leads (common)
3. Defective Dry SSR (occasional)
4. Defective Dry Pump (occasional)

First check

Check if Dry Pump fan blade is stuck

Test point: Dry Pump fan blade
Expected: Blade rotates freely without obstruction

2 more checks with pass and fail actions, 5 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Exhaust Valve opens at the wrong time

Exhaust valve does not open or close according to cycle phase timing

Ranked causes

1. Control signal incorrect or timing problem (occasional)
2. Short in black wire to Solenoid (occasional)
3. Solenoid Coil shorted (occasional)
4. Solenoid connection box loose or defective (occasional)

First check

Measure DC voltage at TP11 and TP1

Test point: TP11 to TP1
Expected: 0 to 1 volt if valve should be open; 10 to 12 volts if closed V, 0-1 V or 10-12 V
Tools: DC voltmeter

4 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Exhaust Valve stays open all the time

Exhaust valve does not close and remains in open position

Ranked causes

1. Control signal continuously energizing solenoid (rare)
2. Ground short in black Solenoid wire (occasional)
3. Solenoid Coil shorted (occasional)
4. Plunger assembly stuck open or damaged (occasional)

First check

Measure DC voltage at TP11 and TP1

Test point: TP11 to TP1
Expected: 10 to 12 volts when valve should be off; 0 to 1 volt when valve on V, 10-12 V off or 0-1 V on
Tools: DC voltmeter

4 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Low temperature during sterilization

LOW TEMP message displayed, Cycle Fail indicator lights, cycle aborts if temperature drops 2.5°C (4.5°F) below required sterilization temperature

Ranked causes

1. Insufficient water in chamber (common)
2. Sterilization phase set too long causing chamber to run dry (common)
3. Safety Thermostat opening prematurely (occasional)
4. Bad Temperature Sensor (occasional)

Printer characters are illegible

Printed text is unclear, smudged, or unreadable

Ranked causes

1. Paper not installed correctly or not thermal paper (common)
2. Printer cable loose or dirty (common)
3. Faulty printer cable or Digital Predg board (occasional)
4. Printer hardware failure (occasional)

First check

Verify paper type and installation

Test point: Printer paper tray
Expected: Thermal paper installed correctly, no scraps in head

2 more checks with pass and fail actions, 4 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Solenoid valve not energizing or operating intermittently patient safety

Solenoid valve fails to energize or operates intermittently; magnet test fails or voltage incorrect across terminals

Ranked causes

1. Loose or corroded solenoid coil terminals/connectors (common)
2. Damaged wire or loose connector (occasional)
3. Solenoid coil defective (occasional)
4. Control problem (occasional)

First check

Magnet test: touch ferrous object to solenoid center post

Test point: Solenoid valve center post
Expected: Strong magnetic attraction when energized
Tools: Steel or iron object

5 more checks with pass and fail actions, 4 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Steam does not exhaust patient safety

Exhaust valve remains closed and pressure does not release from chamber

Ranked causes

1. Debris blocking Exhaust Valve Plunger (common)
2. Loose or broken wire from Solenoid to Electronic Box (occasional)
3. Solenoid Coil shorted or disconnected (occasional)
4. Plunger assembly stuck or damaged (occasional)

First check

Relieve chamber pressure manually

Test point: Safety Relief Valve ring
Expected: Pressure releases safely

4 more checks with pass and fail actions, 5 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Water flow does not stop caution

Water continues to flow through fill system after stop command

Ranked causes

1. Water sensor malfunction or improper control signal (common)
2. Fill valve debris or obstruction preventing closure (common)
3. Fill valve control problem (occasional)
4. Fill solenoid or water pump SSR not receiving correct control voltage (occasional)

First check

Press Stop button on keypad

Test point: Keypad
Expected: Water flow ceases

4 more checks with pass and fail actions, 5 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Water leaks back at end of Exhaust cycle

Water flows back from reservoir into chamber after exhaust phase

Ranked causes

1. Reservoir over-filled (common)
2. Pinhole in Cooling Coil body (occasional)
3. Cooling Coil end below water line (E and EK models only) (common)
4. Check Valve failure (EA, EKA, EZ, EZ10k models) (occasional)

4 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Circuit breaker or fuse trips immediately when unit is turned on high voltage

Circuit breaker or fuse opens as soon as main switch is activated

Ranked causes

1. Incorrect input voltage (common)
2. Ground short at Heating Elements (common)
3. Damaged or shorted wires throughout unit (occasional)

First check

Measure voltage at wall outlet

Test point: Wall outlet
Expected: 110-125V for 110V units; 220-235V for 220V units, ±15V
Tools: DMM

2 more checks with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Circuit breaker or fuse trips while unit is running high voltage

Circuit breaker or fuse opens during autoclave operation

Ranked causes

1. Incorrect input voltage (common)
2. Ground short in Heating Elements (common)
3. Damaged or shorted wires in unit (occasional)

First check

Measure input voltage during operation

Test point: Wall outlet
Expected: 110-125V for 110V units; 220-235V for 220V units, ±15V for 110V units; ±15V for 220V units
Tools: DMM

2 more checks with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Control problem on circuit boards high voltage

Machine malfunction traced to printed circuit boards after mechanical and operator issues eliminated

Ranked causes

1. Damaged cable connectors or loose connections (common)
2. Faulty Digital Predg board (common)
3. Faulty Ajunc board (occasional)

First check

Inspect cable connectors for physical damage

Test point: All connectors inside and outside Electronic Box
Expected: No bent or broken pins, good solid connections

1 more check with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Door Switch indicator always on

Door closed indicator light remains illuminated regardless of door position

Ranked causes

1. Door Switch stuck or sticking (common)
2. Short to chassis in Door Switch wiring (occasional)
3. Digital Predg board or Flat Cable failure (rare)

First check

Verify Door Switch moves freely

Test point: Door Switch
Expected: Moves smoothly in and out

3 more checks with pass and fail actions, 4 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Door Switch indicator operates in reverse

Door closed indicator shows opposite state of actual door position

Ranked causes

1. Door Switch wired to wrong contact (common)
2. Short to chassis in Door Switch wiring (occasional)
3. Digital Predg board or Flat Cable failure (rare)

First check

Verify Door Switch moves freely

Test point: Door Switch
Expected: Moves smoothly in and out

5 more checks with pass and fail actions, 4 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Dry pump makes noise

Pump produces audible noise during operation

Ranked causes

1. Fan blade contacting internal component (common)
2. Bad pump bearing (common)
3. Loose or broken mounting bracket (common)

First check

Verify fan blade clearance

Test point: Dry Pump fan blade
Expected: Blade does not contact housing or internal components

2 more checks with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Low water in chamber

LOW WATER message displayed, Cycle Fail indicator lights, cycle aborts during Heat Up or after power failure if water insufficient to complete cycle

Ranked causes

1. Insufficient water entered chamber at cycle start (common)
2. Water or steam leak from valve or gasket (common)
3. Power down with dry water electrode (occasional)

3 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Low water in chamber during cycle

LOW WATER message displayed; cycle aborted; Cycle Fail indicator lights. Occurs during Heat Up stage or after power restoration if water level insufficient.

Ranked causes

1. Insufficient water entered chamber at cycle start (common)
2. Water or steam leakage from valve, gasket, or fitting (occasional)
3. Water Electrode tip dry after power restoration (occasional)

First check

Verify water level in chamber

Test point: Chamber interior
Expected: Water present at normal operating level

4 more checks with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Power supply has no input voltage high voltage

No voltage present at power supply input despite unit plugged in

Ranked causes

1. Unit not plugged in (common)
2. Wall outlet has no power (common)
3. Power supply fuse blown (common)

First check

Verify unit is plugged into wall outlet

Test point: Power cord connection
Expected: Cord fully seated in outlet

2 more checks with pass and fail actions, 4 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Power supply shuts off intermittently high voltage

Power supply cuts out or resets unexpectedly during operation

Ranked causes

1. Dust buildup on circuit boards in electronic box (common)
2. Incorrect input voltage (too low or high) (common)
3. Loose wire or cable connections (common)

First check

Inspect electronic box boards for dust

Test point: Circuit boards in electronic box
Expected: No visible dust buildup

1 more check with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Solenoid plunger stuck or binding caution

Solenoid plunger not moving freely in and out of sleeve during mechanical operation

Ranked causes

1. Sleeve nicks or distortion (common)
2. Plunger seat irregularities (occasional)
3. Valve base seat irregularities (occasional)

First check

After removing solenoid coil, unscrew plunger assembly from base and clean

Test point: Plunger assembly
Expected: Assembly removed without damage
Tools: Wrenches, cleaning materials

4 more checks with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

SSR load side voltage out of range (110V unit, device off) high voltage

Voltage readings across SSR terminals 1 & 2 incorrect when device is off on 110 volt unit

Ranked causes

1. Problem with line voltage wiring to SSR (common)
2. SSR failed (output stuck on) (occasional)
3. SSR failed (voltage drop too high) (occasional)

First check

Measure AC voltage from terminal 2 to ground with device off

Test point: SSR terminal 2
Expected: 110 to 125 volts AC V, +/-7.5 V
Tools: AC voltmeter

2 more checks with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Water leaking from drain valve caution

Water drips or streams from drain valve during operation or after closing

Ranked causes

1. Debris inside drain valve preventing complete closure (common)
2. Clogged drain tube (common)
3. Worn or damaged inner or outer O-rings (common)

First check

Inspect drain valve interior for debris

Test point: Drain valve inside end
Expected: Clean, no debris

2 more checks with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Chamber heating not starting caution

During IN-OUT test HEATERS item, heating elements do not activate or display does not show heating

Ranked causes

1. Heating element control circuit not energizing (common)
2. Open heating element or internal connection failure (occasional)

First check

Measure heater control output voltage at TP12

Test point: TP12 on AJUNC 2 or AJUNC 3 board
Expected: 0 to 1 v = heater ON; 3.5 to 5 v = heater OFF
Tools: Digital multimeter

2 more checks with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Display backlight very faint

LCD display backlight is dim or faint, making text hard to read

Ranked causes

1. Incorrect +5V supply to display backlight (common)
2. Damaged LCD display (occasional)

First check

Measure backlight power supply voltage

Test point: TP17 to TP1
Expected: +5 volts DC V

2 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Dry pump does not turn off

Pump runs continuously even after door opened or stop button pressed; continues for up to 2 hours if door remains closed

Ranked causes

1. Control signal not reaching Dry SSR (common)
2. Dry SSR not responding to control signal (common)

First check

Measure control signal voltage at test point

Test point: TP20 and TP1 (TP18 and TP1 for Ajunc 2 board)
Expected: 3.5 to 5 volt DC to turn off; 0 to 1 volt to turn on V, 3.5-5 or 0-1
Tools: DVM

1 more check with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Dry Pump operation differs between control microprocessor versions

Dry Pump behavior and operation method varies based on equipment firmware version (T96DN1 vs T97N6)

Ranked causes

1. T96DN1 firmware: pump requires door closed and cycle restart after door opening (common)
2. T97N6 firmware: pump runs regardless of door position (common)

First check

Identify equipment microprocessor version

Test point: Control board identification or service menu
Expected: T96DN1 or T97N6 designation
Tools: Visual inspection or setup menu

2 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Feed button does not advance paper

Paper does not move when FEED button is pressed

Ranked causes

1. Paper not positioned high enough for sensor detection (common)
2. Faulty paper out sensor or printer hardware (occasional)

First check

Check Paper Out Light status

Test point: Paper Out Light on Printer
Expected: Light not lit when paper is in tray

1 more check with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Float Switch indicator operates in reverse

Water level indicator shows opposite state of actual Float Switch position

Ranked causes

1. Float Switch installed upside down (occasional)
2. Digital Predg board or Flat Cable failure (rare)

First check

Verify Float Switch moves freely

Test point: Float Switch
Expected: Moves smoothly up and down

2 more checks with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Heating elements out of resistance specification caution

Group resistance reading of heating elements not within +/- 10% of specification or ground resistance exceeds limits

Ranked causes

1. One or more heating elements failed (common)
2. Internal heating element damage from wire twisting (occasional)

First check

Measure resistance across heating element terminals (group)

Test point: Any two heating element terminals (elements wired together)
Expected: See Ohm & Amp Readings Table [sec 9.1] +/- 10%
Tools: Ohmmeter

1 more check with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

High pressure during sterilization

HIGH PRES message displayed, Cycle Fail indicator lights, cycle aborts if pressure rises 10 PSI (0.6 BAR) above required sterilization pressure

Ranked causes

1. Heating Elements remaining on instead of cycling (common)
2. Sterilization temperature set above 274°F (occasional)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

More symptoms

High temperature during sterilization
Low heat: chamber does not reach sterilization temperature
Power supply has no output voltage
Spore tests failing or indicator strips not turning
SSR control voltage does not switch when device on
SSR control voltage out of range when device off
SSR load side voltage incorrect (110V unit, device on)
SSR load side voltage incorrect (220V unit, device off)
SSR load side voltage incorrect (220V unit, device on)
Water does not enter chamber
Water fill takes longer than usual
Water Pump blows fuse
Water Pump does not turn off
Water Pump makes noise
Water pump not operating
Air flows in wrong direction
Air outlet valve not operating
Air pump not operating
Ajunc board failure with output voltage loss
Calibration: Automatic water fill system
Calibration: Chamber pitch adjustment
Calibration: Pressure sensor (Ajunc2 board)
Calibration: Pressure sensor (Ajunc3 board)
Calibration: PT-100 temperature sensor (Ajunc3 board)
Calibration: Water pump fill (units with WP date code)
Cut-Out Thermostat does not reset
Cut-Out Thermostat reset button will not reset
Cut-Out Thermostat trips too soon
Date and time not saved
Door switch malfunction
Dry valve and dry pump not operating
Exhaust valve not opening
Fan control not responding
Float switch malfunction
No continuity across Cut-Out Thermostat
Pressure transducer not reading
Printer prints upside down
Safety Thermostat has no continuity
Safety thermostat not detecting or grounding
SSR electrical continuity failure
Temperature sensor calibration: LM34 sensor (Ajunc 2 board)
Temperature sensor not reading
Test: Safety thermostat - device does not reset
Test: Safety thermostat - trips too soon (Ajunc2 board)
Test: Safety thermostat - trips too soon (Ajunc3 board)
Test: Safety thermostat - trips too soon (hard-wired)
Test: Water sensing electrode function
Test: Water sensing electrode with ohmmeter
User parameters not saved
Water flows in wrong direction
Water level electrode not responding

51 more symptoms with ranked causes and checks are in ServiceForge. Connect ServiceForge to your AI

Error codes

Code	Meaning	Trigger	Severity
`ADD WATER`	Insufficient water in Water Reservoir	Water level low in Reservoir	warning
`CYC FINISHED`	Cycle completed successfully	End of successful sterilization cycle	info
`DOOR UNLOCK`	Door improperly closed or accidentally opened during cycle	Door not fully closed when START pressed, or door opens during cycle operation	error
`HIGH PRES`	Pressure exceeded limit during sterilization	Pressure rises 10 PSI (0.6 BAR) above required sterilization pressure	error
`HIGH TEMP`	Temperature exceeded limit during sterilization	Temperature rises 9°F (5°C) above required sterilization temperature or Temperature Sensor damaged	error
`LOW HEAT`	Chamber temperature did not reach sterilization temperature within time limit	Detected after 50 minutes (Wrapped/Unwrapped) or 80 minutes (Liquid) without reaching sterilization temperature	error
`LOW HEAT`	Sterilization temperature not reached after heating period	Temperature not reached within 50 min (Wrapped/Unwrapped) or 80 min (Liquid program)	error
`LOW PRES`	Pressure dropped during sterilization phase	Pressure drops 4 PSI (0.27 BAR) below required sterilization pressure	error
`LOW TEMP`	Temperature dropped during sterilization phase	Temperature drops 2.5°C (4.5°F) below required sterilization temperature	error
`LOW WATER`	Insufficient water in chamber to complete cycle	Water level insufficient during Heat Up or insufficient water on power restoration check	error
`MAN STOP`	Cycle manually stopped by operator	STOP Key depressed for longer than 1 second	info
`POWER DN`	Power failure occurred during cycle	Power loss and restoration during cycle operation	warning
`RENEW WATER`	Water Reservoir requires cleaning and refilling	Informational message during normal operation	info
`WATER INLET`	Water entering chamber during fill	During automatic water filling process	info

Likely causes and actions for each code are in ServiceForge. Connect ServiceForge to your AI

Community

0 fixes logged by technicians through their AI, with outcomes, for this model.

ServiceForge knowledge base record. Field-unverified unless technicians confirmed it. A teaching summary of the record, not a service manual. Export 2026-10-14.