STERRAD NX- Sterilization System Service Troubleshooting Guide RevA Service Manual 2005

STERRAD® NX™ Sterilization System

Service Troubleshooting Guide

1-888-STERRAD (1-888-783-7723) ASP USA Customer Care Center www.sterrad.com International Technical Support 001.949.581.5799 ASP International Customer Support (Call your local ASP Customer Support Representative)

© 2005. Advanced Sterilization Products. All rights reserved. Other products mentioned in this publication are trademarked by their respective owners. Reproduction, adaptation, or translation of this publication without prior written permission is prohibited. Printed in the U.S.A. 08-53528-0-001 2

TS-53527-0-001 Rev A STERRAD® NX™ Service Guide

Contents Chapter 1. Introduction

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Overview ...7 Sterilant and Cassette...8 Hardware ...8 Software...8 Chapter 2. Safety Information

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Personal Safety and First Aid ...11 Cassette Handling ...13 Personal Protection Equipment...13 Warnings, Cautions, and Notes...14 Symbols Used on the Sterilizer and in This Guide ...14 Safety Standards Compliance ...15 Chapter 3. Functional Description

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Overview of the Sterilization Process...17 Hydrogen Peroxide Concentration and Delivery ...18 Process Monitoring and Control ...18 Temperature ...19 Pressure...19 Hydrogen Peroxide Monitor ...19 Plasma Power...20 Time ...20 System Software ...20 Functional Block Diagram...22 Subsystems ...23 Hydrogen Peroxide Delivery Subsystem ...23 Vaporization Subsystem ...23 Vacuum Subsystem...23 Plasma Subsystem...23 Hydrogen Peroxide Monitor Subsystem ...23 Modular Design ...24 Modules and Subsystem Details ...25 Top Module ...27 Chassis ...27 Access Panels...28 Display Assembly ...28 Cassette Drawer ...28 Delivery System...28 Vaporizer/Condenser ...28 Power Inlet Connector ...28 AC Distribution...29 DC Power Supply ...29 System Controller ...29 Fan ...29 Chamber Module ...30 Access Panels...30 Door Assembly ...30 Chamber and Shelves...31 Electrode ...31 STERRAD® NX™ Service Guide

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Feedthrough... 31 Base Module ... 32 Frame and Chassis... 33 Access Panel... 33 Circuit Breaker ... 33 LFPS II Power Supply... 33 Printer... 33 Vacuum Pump Assembly ... 33 Diagnostic Functions and Tests ... 34 Subsystems and Components ... 34 Door Heater Resistance Configuration... 36 Process Variables and Cancellation Limits ... 37 Chapter 4. Diagnostic Tests and Error Messages

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Diagnostic Files ... 39 Diagnostics... 39 Diagnostic Tests ... 40 Troubleshooting ... 42 Error Messages... 42 Diagnostic Messages ... 47 Chapter 5. Subassembly Removal and Replacement

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Access to Sterilizer Interior... 53 Front Top Panel (02-51326) ... 54 Top Panel (33-51196)... 55 Rear Top Panel (33-51197) ... 56 Front Bottom Panel (33-51195) ... 57 Right Side Panel (33-51193) ... 58 Left Side Panel (33-51193) ... 59 Door Cover (33-51993) ... 60 Top Module... 61 Delivery System Assembly (02-51984) ... 61 Delivery Valve ... 63 Delivery Subsystem Inlet Filter (PM kit part 25-50703)... 63 Air Pump Tubes ... 63 Vaporizer/Condenser Assembly (02-52410) ... 64 Vent Valve (28-51218)... 66 Chamber Pressure Control Assembly (02-52387)... 68 Circuit Boards Assembly: Universal Control Board (UCB) (04-50361) and Interface Board (0452006) ... 70 Alternating Current (AC) Distribution Assembly (02-51959) ... 72 Direct Current (DC) Power Supply (40-51141) ... 74 Display Assembly (40-50532)... 76 Fan Assembly (04-51991) ... 78 Door Lock Solenoid (42-52001) and Door Lock Sensor (04-51990)... 79 Power Inlet Connector (45-51407)... 80 Ultraviolet Lamp Power Supply (40-51449) ... 81 Hydrogen Peroxide Monitor Lamp Assembly (04-50544)... 82 Chamber Module ... 84 Electrode Assembly (03-51157) Spacers and Slides (35-51152), Lower Shelf Stop (35-51153), Upper Shelf Stop (33-51158) ... 84 Door Assembly (03-51985)... 85 Door Seal O-Ring (22-00537) ... 87 Latch Assembly (74-51398)... 88

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Hydrogen Peroxide Detector Assembly (04-52108) ...89 Base Module ...90 Vacuum Pump Assembly (04-52158) ...90 Catalytic Converter (25-05611) ...92 Catalytic Converter (25-05611) ...92 Oil Mist Filter (25-51970)...93 Vacuum Control Valve (28-51216) ...94 Oil Return Valve (28-51971) ...95 Low Frequency Plasma System (LFPS II) (40-52154) ...96 Printer Assembly (04-51482)...97 Circuit Breaker (57-52105) ...99 Chapter 6. Planned Maintenance

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Overview ...101 Vacuum Pump Oil Replacement...102 Catalytic Converter Replacement ...103 Oil Mist Filter Replacement ...103 Air Filter Replacement...103 Vent Valve HEPA Filter Replacement ...103 Hydrogen Peroxide Detector Lamp ...104 Delivery Subsystem Inlet Filter Replacement ...105 Air Pump Tubes Replacement ...105 Door Seal O-Ring Replacement ...106 Chamber/Electrode/Plastics ...107 Thermistor Replacement...107 Chamber Thermistor Replacement...107 Door Thermistor Replacement...108 Condenser/Vaporizer Thermistors Replacement...109 Cassette Disposal and Printer Maintenance ...109 Replacing a Cassette Disposal Box...110 Inserting a New Cassette Disposal Box ...110 Cleaning the Thermal Printer Head...111 Replacing the Printer Paper...112

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Chapter 7. System Calibration and Verification

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Overview... 115 Service Action Table... 115 Zeroing Pressure Transducers ... 116 Leak Test... 117 Plasma Power Delivery Verification... 118 Temperature Calibration Using A Temperature Bath or Precision Resistors... 119 Peroxide Calibration With Neutral Density Filters ... 122 Diagnostics ... 123 Temperature Verification ... 123 Appendix A. STERRAD® NX™ Sterilizer Specifications

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Introduction

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Chapter 1.

Introduction Overview The STERRAD® NX™ Sterilizer is a self-contained stand-alone system of hardware and software designed to sterilize medical instruments and devices using a patented hydrogen peroxide gas plasma process. Hydrogen peroxide vapor is generated by delivering aqueous hydrogen peroxide into the vaporizer where the solution is heated and vaporized. The hydrogen peroxide vapor is then introduced into the sterilization chamber, under sub-ambient pressure, where it is transformed into a gasplasma by use of electrical energy. The STERRAD NX Sterilizer is designed for low temperature sterilization of both metal and nonmetal medical devices. Because the cycle operates within a dry environment and at low temperatures, it is especially suitable for instruments sensitive to heat and moisture. The STERRAD NX Sterilizer employs a modified method of delivering hydrogen peroxide to sterilize devices within the sterilization chamber. This modified process concentrates the 59% hydrogen peroxide to 90% nominal hydrogen peroxide (by selectively vaporizing and removing water) prior to being transferred into the sterilization chamber. In addition, by using the concentrated hydrogen peroxide solution, the sterilization cycle times have been reduced.

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Introduction

Sterilant and Cassette The sterilant used in the STERRAD NX Sterilizer is hydrogen peroxide. It is supplied in cassette form as a separate accessory. The cassette shell is made of white, high impact polystyrene. Each cassette encapsulates 10 individually sealed cells. Each of the filled cells of the cassette contains 1800 µl (±50 µl) of 59% nominal hydrogen peroxide. Each sterilization cycle uses two cells; therefore, a cassette can process five sterilization cycles.

Hardware The hardware for the sterilizer consists of a sterilization chamber and a variety of instruments and components which are housed in a covered frame. The sterilizer system also uses accessories such as a disposable sterilant cassette, reusable instrument trays, printer paper, and an optional movable cart. The STERRAD NX Sterilizer can be placed directly on a table, counter top, or on the movable cart.

Software The sterilization process is controlled automatically by software. The software controls and monitors the hardware through digital and analog signals. Functions managed by software include: ♦ Time ♦ Temperature/pressure measurement and control. ♦ Sterilant delivery and vaporization. ♦ Plasma power generation and measurement. ♦ Hydrogen peroxide monitor ♦ Access to chamber through lock-controlled door.

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Introduction

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Each parameter is part of a control loop in which information flows as input from one of many sensors to the computer, where it is processed and triggers an output signal which flows from the computer to an output device. Through this system of feedback signals (input), analysis, and response signals (output), the computer controls the entire sterilization process. If any process parameter falls outside allowable ranges, the software will cancel the cycle. 4 Note: The hydrogen peroxide monitor does not provide feedback control to the sterilizer. However, the monitor will cancel the cycle if the area under the hydrogen peroxide concentration-time curve or hydrogen peroxide rate constant does not meet specifications.

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Safety Information

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Chapter 2.

Safety Information Your safety is of primary concern to Advanced Sterilization Products. This chapter provides information on safely servicing the STERRAD® NX Sterilizer. You must read and understand the safety information in this chapter before performing service on the sterilizer. Always pay attention to the warnings, cautions and notes throughout this Service Guide.

Personal Safety and First Aid WARNING! HYDROGEN PEROXIDE IS CORROSIVE. Concentrated hydrogen peroxide is corrosive to skin, eyes, nose, throat, lungs, and the gastrointestinal tract. Always wear latex, PVC (vinyl), or nitrile gloves while removing items from the sterilizer following a cancelled cycle. Following a cancelled cycle, if items in the load show any visible moisture or liquid, hydrogen peroxide may be present. WARNING! HYDROGEN PEROXIDE IS AN OXIDIZER. Avoid allowing hydrogen peroxide to contact organic materials, including paper, cotton, wood, or lubricants. Concentrated hydrogen peroxide is a strong oxidizer and may react with organic materials, causing ignition and fire. WARNING! RISK OF EYE INJURY. Direct hydrogen peroxide contact with eyes can cause irreversible tissue damage. If contact with eyes occurs, immediately flush with large amounts of water. Consult a physician immediately. WARNING! RISK OF SKIN INJURY. Direct hydrogen peroxide contact with the skin can cause severe irritation. If skin contact occurs, immediately flush with large amounts of water. If symptoms are severe or persist, consult a physician immediately. WARNING! RISK OF RESPIRATORY IRRITATION. Inhalation of hydrogen peroxide mist can cause severe irritation of lungs, throat, and nose. If inhalation occurs, move to fresh air. Consult a physician immediately. STERRAD® NX™ Service Guide

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Safety Information

WARNING! CONCENTRATED HYDROGEN PEROXIDE IS TOXIC. Ingestion of hydrogen peroxide may be life-threatening. If swallowed, drink plenty of water immediately to dilute. Do not induce vomiting. Consult a physician immediately. WARNING! HOT SURFACES. Components in the interior of the sterilizer may be hot. Do not touch the inside of the chamber or door with your bare or gloved hands when the sterilizer is operating. Allow the sterilizer to cool before touching interior surfaces. CAUTION: AVOID EXPOSURE TO ULTRAVIOLET LIGHT. The hydrogen peroxide monitor uses an ultraviolet light source located inside the chamber behind the door. To avoid eye injury, do not stare directly at the ultraviolet light source for an extended period of time. Use protective eyewear if necessary. WARNING! ELECTRIC SHOCK HAZARD. High voltages are present inside the sterilizer. Contact with electrically energized parts can cause injury or death. Turn OFF and unplug the sterilizer before performing service tasks.

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Cassette Handling STERRAD CASSETTES CONTAIN CONCENTRATED HYDROGEN PEROXIDE, A STRONG OXIDIZER. CONCENTRATED HYDROGEN PEROXIDE IS CORROSIVE TO SKIN, EYES, NOSE, THROAT, LUNGS, AND GASTROINTESTINAL TRACT. Direct contact with the skin can cause severe irritation. If skin contact occurs, immediately flush with large amounts of water. If symptoms are severe or persist, consult a physician immediately. Direct contact with eyes can cause irreversible tissue damage. If eye contact occurs, immediately flush with large amounts of water and immediately consult a physician. Inhalation of vapor or mist can cause severe irritation of lungs, throat, and nose. If inhalation occurs, move to fresh air and consult a physician immediately. Ingestion can produce corrosion that may be life threatening. If swallowed, immediately drink plenty of water to dilute. Do not induce vomiting. Consult a physician. Do not remove the plastic wrapper from the cassette package if the indicator strip is red. Red indicates that the cassette might have been damaged. Call your ASP representative for credit. Do not remove used cassettes from the cassette collection box. Dispose of the sealed cassette collection box according to local waste regulations. Cassettes with unused hydrogen peroxide are hazardous waste as defined by the Environmental Protection Agency (USA) and should be disposed of accordingly. If it is necessary to handle a used cassette, wear latex, PVC (vinyl), or nitrile gloves. Do not touch gloves to face or eyes. Empty or expired cassettes must be replaced prior to starting the cycle as directed by a message on the sterilizer display. Cassettes with unused hydrogen peroxide are hazardous waste as defined by the Environmental Protection Agency (USA) and should be disposed of accordingly.

Personal Protection Equipment Wear latex, PVC (vinyl), or nitrile gloves whenever handling a load after a cycle cancellation. Hydrogen peroxide liquid may be present on the load or in the chamber.

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Safety Information

Warnings, Cautions, and Notes

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Warnings and cautions are accompanied by symbols surrounded by a triangle and are printed in the text in bold. Warnings indicate events or conditions that can result in serious injury or death. Cautions indicate events or conditions that can result in severe damage to the equipment.

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Notes are printed in italics and have a checkmark in front of the word “Note.” Notes highlight specific information about the proper use and maintenance of the STERRAD® NX™ Sterilization System.

Symbols Used on the Sterilizer and in This Guide Hot surfaces present. Do not touch without protection. Hazardous chemical present. Use personal protective equipment. Toxic chemical present. Avoid exposure, contact, or ingestion. Ultraviolet (UV) light hazard. Do not look at the light without UV eye protection. High voltage hazard.

I/O

On/Off. Alternating current.

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Safety Standards Compliance The STERRAD® NX™ Sterilizer meets the following safety standards: ♦ CAN/CSA-C22.2 No. 1010.1B: 1997; Safety Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use. ♦ UL 61010A-1: 2002; Standard for Safety for Electrical Equipment for Laboratory Use. ♦ EN 61010-1: 2001; Safety Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use. ♦ EN 61010-1-2: 2001; Medical Electrical Equipment, Part 1: General Requirements for Safety, Section 2: Collateral Standard: Electromagnetic Compatibility. ♦ IEC 60601-1-2; Medical Electrical Equipment. Part 1-2 General Requirements For Safety. Collateral standard: Electromagnetic Compatibility.

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Functional Description

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Chapter 3.

Functional Description Overview of the Sterilization Process The STERRAD® NX™ Sterilizer software interfaces with the hardware through digital/analog input and output signals and through serial communications via serial ports. The inputs monitor the sterilization process while the outputs control the process. The process occurs as follows: 1. The items to be sterilized are placed in the sterilization chamber, the chamber door is closed, and a vacuum pump reduces the pressure in the chamber. 2. A 59% aqueous solution of hydrogen peroxide is injected into the delivery system condenser where it is condensed and concentrated and then introduced into the chamber. 3. A low frequency electric current is delivered to the chamber electrode, causing the formation of a low temperature gas plasma in the chamber. 4. In the plasma state, the hydrogen peroxide vapor breaks apart into reactive molecules that include free radicals. 5. The combined use of hydrogen peroxide and plasma safely and rapidly sterilizes most medical instruments and materials without leaving toxic residues.

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Functional Description

Hydrogen Peroxide Concentration and Delivery During the hydrogen peroxide delivery step, hydrogen peroxide solution is delivered into the vaporizer bowl at atmospheric pressure conditions. Air is removed from the chamber and from the vaporizer/condenser by pulling a vacuum to a controlled pressure in the vaporizer/condenser. At this time, the transfer valve is closed. Water is removed from the 59% hydrogen peroxide solution by reducing the pressure in the condenser. The pressure differential between the chamber and the condenser creates the driving force to remove the water. During this concentration step, the flow of water vapor is restricted by an orifice between the condenser and the chamber, creating lower chamber pressure. Once the controlled pressure is achieved in the condenser, the chamber pressure is further reduced by closing the orifice with the transition valve. The condenser temperature is increased and the concentrated hydrogen peroxide vapor is then transferred into the chamber by opening the transfer valve and the transition valve. This transfer step is followed by the diffusion step (which occurs at atmospheric pressure), followed by pressure reduction and plasma. The vent step then occurs which returns the chamber to atmospheric pressure. This process occurs twice during a complete sterilization cycle.

Process Monitoring and Control The monitoring and control systems regulate the following: ♦ Temperature ♦ Pressure ♦ Hydrogen peroxide monitor ♦ Plasma power ♦ Time ♦ Process status ♦ IMS

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Temperature Temperature monitoring and control are involved in two aspects of the STERRAD NX Process: heating and cooling of the condenser that condenses hydrogen peroxide during vaporization, and heating the vaporizer, chamber walls and door. The temperature control loop consists of heaters and temperature sensors. There are five temperature sensors in the system. The are located on the vaporizer, condenser, door, chamber front, and chamber rear.

Pressure Pressure monitoring and control are performed by a control loop which includes the vacuum pump, vacuum control valve, vent valve, three pressure transducers and an atmospheric pressure switch. The control system interacts with these components during chamber evacuation, pressure monitoring, and venting to atmosphere. Two chamber pressure transducers monitor and control the vacuum process; one ranges from 030 torr and the other ranges from 0-200 torr. The pressure transducers are attached to a port in the top of the chamber. The vaporizer pressure transducer monitors and controls the vacuum during the vaporization pumpdown step; its range is from 0-30 torr. The pressure transducer is attached to a port in the vaporizer/condenser assembly. The atmospheric pressure switch is a differential pressure sensor. Its function is to signal the control system that the interior of the chamber is at or very near atmospheric pressure.

Hydrogen Peroxide Monitor During the hydrogen peroxide transfer step, hydrogen peroxide concentration data are collected from the monitor. The ultraviolet lamp assembly sits at the top front of the chamber and delivers UV light across the chamber to the detector mounted at the bottom of the chamber. Hydrogen peroxide vapor absorbs UV light – reducing the intensity of light reaching the detector by an amount proportional to the amount of hydrogen peroxide present in the light path. A photodiode detector measures the amount of light coming from the lamp, before and during hydrogen peroxide transfer to the chamber, allowing a calculation of the hydrogen peroxide concentration. The area under the concentration-time curve and the hydrogen peroxide rate constant are calculated and compared to specifications, by the controller. If the limits are exceeded, the cycle is cancelled.

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Functional Description

Plasma Power The plasma power monitoring and control system controls the plasma power during the two plasma steps of the STERRAD NX Sterilizer process. The plasma power is monitored and controlled by a plasma power sensor. This sensor interacts in a control loop with the computer and plasma power unit to control the process within the specified limits.

Time Time monitoring and control are performed by the computer and affect numerous steps in the process. An interval timer measures process step duration and the computer uses time inputs to control the various devices in the process sequence.

System Software STERRAD NX Sterilizer software controls and monitors the sterilizer through digital and analog signals. When a sterilization cycle is not in process, the software monitors and controls the sterilizer temperature, responds to operator touch panel inputs (Select Cycle and Start Cycle), verifies cassettes upon insertion, controls printer output, and allows the operator to set the system date and time. When a sterilization cycle is in process, the software controls and monitors the timing, temperature, pressure, delivery and vaporization processes, application of plasma power, printer output, and responds to an operator input of CANCEL (all other operator inputs are disabled during the cycle). If sterilization process parameters fall outside allowable ranges, the software will cause the cycle to cancel, and will control the cancellation process. Each sterilizer subsystem is part of a control loop in which information flows as input from one or more sensors to the computer, where it is processed and triggers an output signal which flows from the computer to an output device. Through this system of feedback signals (input), analysis, and response signals (output), the computer controls the entire sterilization process.

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Functional Description

Figure 1. Software Control Diagram.

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Functional Description

Functional Block Diagram A functional block diagram of the STERRAD NX Sterilizer is illustrated in the following figure.

VGA

DC Power Supply

Touch Interface

USER INTERFACE

Test points, LED status, Buffers, Filters, Drivers, Beeper

Analog Input Digital Output Digital Input

ULCC BOARD (SYSTEM SOFTWARE)

Analog Output

VGA

Serial Interface Synchronization DC Power & Filter

TE Driver

CONDENSOR

Serial Interface Status & Control DC Power & Filter

Scaner

Serial Interface Status & Control DC Power & Filter

PRINTER

Status & Control Analog Input & Filter Safety circuit

DOOR CONTROL

Status & Driver DC Power

INTERFACE BOARD

Thermistors HEATING CONTROL

Vacuum Pump Pressure Transducer ATM Switch Vacuum Valve Vent Valve

Status & Control Analog Input & Filter DC Power

VACUUM CONTROL

Status & Control Analog Input & Filter DC Power

Piercing motor Guide Motor Air pump

Status & Control Analog Input, Output & Filter, DC Power

FANS

Vaporizer Heaters

Status & Control Analog Input & Filter

Power Condition

AC POWER CONFIGURATION, DISTRIBUTION & CONTROL

PLASMA CONTROL

Status & Control DC Power & Filter

Delivery valve Cassette sensor PEROXIDE DELIVERY

PEROXIDE MONITOR

Figure 2. Functional Block Diagram

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