SECTION 5-1 TROUBLESHOOTING PROCEDURES - ALARMS

Free Autoclave Troubleshooting Guides



SECTION 5-1 VALIDATOR PLUS TROUBLESHOOTING PROCEDURES


OPERATING ALARMS

During the sterilization cycle, there are seven alarms which may occur.
  • The "door" alarm indicates that the door switch is not actuated, and the door must be closed to start or run a cycle.
  • The water ("H20") alarm means that the temperature at the front bottom surface of the chamber is too hot, presumably because no water is left to boil. This alarm prevents the heating element from overheating and burning out.
  • The "FAIL" alarm indicates that program sterilization parameters could not be reached in the time allot3ed (45 minutes from start), a three-minute or longer pause occured during the sterilize portion of the cycle, it took seven minutes to complete the air-bleeding process or the door was opened after "FILL" cycle was finished

    Under the first three conditions the display is continuous and for the last condition the display will flash. The "FAIL" alarm shows that the unit could not build or maintain pressure.
  • The "P-1" alarm illuminates when the pressure transducer circuit is inoperative.
  • The "P-2" alarm illuminates when the displayed pressure reaches 241 kPa indicating that either air bleeding was insufficient or has a defective steam or pressure sensor
  • The "SS-1" alarm illuminates if temperature sensor is defective or if autoclave temperature is less than 10 ° C
  • The "SS-3" alarm illuminates if the microprocessor senses that the steam temperature reading has exceeded a maximum value of 140 ° C.
All alarms produce "beeps" for one minute (or until the problems are corerected by the operator), and the indication is shown in the lower display window.

The alarm display readings are shown until the operator depresses the "CLEAR/START" button. (The display reading should be recorded prior to depressing the "CLEAR/START" button, becuase depressing the button may also clear the display reading. (The "door" alarm is cleared if the door is closed) Refer to table 5-1 for possible causes.
DISPLAYPROBLEMACTION
DOOR
All problems listed here also apply to "FAIL"
Door not fully closed during fillCheck Door Closure
--Check D21 LED on Driver Interface Board. D21 lights up if door is open or switch is disengaged
-Door Switch is not properly aligned.Remove Switch cover plate at bottom right of chamber front. Adjust door switch for more contact with door latch.
-Faulty switch, wire or connectionUse D21 to check operation. Check switch and wire seperately for continuity
H20Surface Sensor is heat sensitive and opens at 159 ° C. Surface Sensor opens if

a) water does not get into the chamber.
Check Water Path:


a) Check for clogged fill valve, remove fill filter inside reservoir. Run a cycle, then re-install filter

Pour water directly into the chamber and then start a cycle.

Check amount of distilled water in reservoir. If low, add water unhtil it reaches bottom of fill cup.
-Defective Fill/Vent Solenoid.Run self-diagnostic check. The S-1 check will test continuity of solenoid coil.
-Defective Dump SolenoidRun self-diagnostic check. The S-2 check will test continuity of solenoid coil. If continuity checks okay, thena solenoid is stuck or tubings are clogged. Check for clogged fill filter inside reservoir and inside chamber. Clean filter in ultrasonic cleaner if required

Rerun cycle. Open door during fill cycle to see if water enters chamber. Remember to close door before fill cycle is complete.
-b) water does not stay in chamber:

Various valve leaks (with unit under pressure)

Fill/Vent Valve - bubbles around pipe in bottom of reservoir.

Dump valve-steam emitted from hex brass fitting at top of square opening in reservoir

Bellows Valve - water spurts from condensor coil
b)Observe reservoir while chamber is presuurized to determine where water is being returned to reservoir. Clean appropriate valve seat or replace appropriate valve
-c) Surface Temperature Sensor is faultyc) Unplug and test sensor at room temperature for continuity. If no continuity, replace sensor.
-Leaking Door Gasket:

Steam leaking & Water Dripping
If load blocks gasket, clear the load. Clean gasket. Check for position. If these fail, replace gasket
FAILUnit takes more than 45 minutes to reach operating temperature Check chamber for overloading

Check for valve leaks (Same as H20). Check valves, fittings, and gasket for steam leaks.
-More than three-minute lapse in sterilize countdown due to leak causing more the 4 kPa pressure decreaseCheck Safety Valve for seepage at normal operating pressure. Replace if defective
-Overheat Protector opening too soon. Overheat LED is normally never illiminated)No Heater power or insufficient heater powerReplace defective Sensor
-No heater power or insufficient heater powerCheck amperage draw (See Table 10-2). In insufficient amperage, check heater resistance with an ohm meter (See Table 10-2). If heater is working, replace the MOC chip on the driver board with a MOC 3041 chip. Plug chip in with dot toward the transformer. If this does not correct the problem, replace the driver board.

Check D22 LED on Driver/Interface Board. If plugged into 220V outlet, relay switch light should be off. If heater relay switch LED is in wrong mode, replace Driver/Interface Board.

Check heater LED D15 on Driver/Interface Board.

Check heater LED on MPU Board. If LEP on MPU Board does not flash then change MPU Board. If LED on MPU Board flashes but LED on Driver/Interface Board does not, then check interconnecting ribbon cable. If cable is okay, replace Driver/Interface Board.
-Door opened after fill or door switch circuit is brokenCheck switch alignment & cable, see DOOR alarm
-Takes more than 7 minutes for temperature to rise from 90 ° C to 110 ° CCheck D22 LED. (Also see above: No Heater power.")

Pressure calibration incorrect, replace Driver/Interface Board
-Defective relay (90V~132V~ only)This can be determined by measuring the current through Pin 3 of P6 (Heater cable). If there is no current when the D15 is on, the realy is bad. Replace Driver/Interface Board.
P-1Pressure Sensor our of calibration or not workingCheck Sensor output by using test points on Driver/Interface Board. Measure TP10 to ground. Reading should be 10mVkPa.

Example: 10kPa should equal 100mV
Check TP4 at Driver/Interface Board and MPU Board. Voltmeter reading should be 17VDC or above. If not, Display Board or ribbon cable may be the cause of the problem.

Check TP6 to ground. Readin should be 15VDC.

If above checks pass, then the problem is the pressure transducer circuit. Replace the Driver/Interface Board
P-2Unit reaches 241 kPa without displaying 135 ° C.Replace Steam Sensor
-Bellows Solenoid does not open or close between 98 ° C and 111 ° C. No saturated steam.a) Check power and resistance of Bellows Solenoid. If defective, replace Bellows Solenoid.

b) Check for interference in the Bellows Solenoid line. Clean or replace line.
-Heater power never cuts back. Make sure that heater power LED D15 flashes as unit reaches desired temperature. Triac is defective. Replace Driver/Interface Board
SS-1Pressure Sensor is not in calibration (i.e. reads too high)Replace Driver/Interface Board
-Temperature display does not changeReplace Steam Sensor
-Temperature is less than 10 ° CIf unit is cold, let it warm up for a while before attempting to operate
-Temperature Sensor is bad or unpluggedUse digital meter and measure between test points TP11 & TP5 for reading. Digital meter should agree with temperature display and vary 10mV for ever degree C. Example: 25 ° C will read as 250mV
SS-3Steam temperature too high (>140 ° ).Check steam temperature on front panel display
-Pressure Sensor out of calibrationCheck steam temperature sensor cable. Replace.
No DisplayUnit won't turn onSee Usage Problems (Section 5-3)



allclaveparts.com widget logo