Common Steam Autoclave Maintenance Questions, Answered

Amit Gupta
Written by: Amit Gupta

MS Mechanical Engineering, Vice President of Engineering

Maintaining steam autoclaves in proper working order improves productivity, reduces downtime, extends the life of the autoclave, and helps to ensure overall safety in the workplace. So, to help you maintain your autoclave, we wrote about the importance of autoclave maintenance and shared some basic tips to maintain your equipment in a prior post.

In this post, we take the conversation a little deeper, answering common maintenance questions and identifying the critical components on an autoclave that should be inspected periodically by a trained service provider. This is not an exhaustive list of all the autoclave components that should be inspected but merely the major ones.

Q. What Autoclave Maintenance Options Are Available to Me?

A. There are two ways to approach autoclave maintenance, both of which should be included in your maintenance plan: self-service and professional service. Self-service is exactly what it sounds like: small-scale maintenance performed by you or another member of your team. These actions can help prevent larger issues from developing and should take place on a fairly regular basis, which we’ll explain in detail in an upcoming question.

For other essential maintenance — think, repairs, inspections, and more in-depth service, such as recalibrating temperature and pressure sensors — you’ll want to call in a professional. How often you need to seek professional service will depend on a few different factors, including your daily autoclave usage and water quality, but can range anywhere from once per year to once per quarter.

Q. What Should My Self-Service Maintenance Schedule Look Like?

A.  There are a few simple measures you can take on a daily, weekly, and monthly basis to ensure that your autoclave operates smoothly:


  • Make sure that the chamber drain strainer, which can be found in the front drain hole of the sterilizer, is free of debris. It’s important to do this at least once per day because a clogged chamber drain strainer will prevent your autoclave from sensing temperature.
  • Immediately wipe up any spills in the autoclave chamber with a chamber cleaning solution, such as C3 Chamber Cleaner, and cleaning pads. Do not use hypochlorites that contain bleach, corrosive chemicals, acids or seawater, as these can damage the stainless steel chamber.
  • If your autoclave is equipped with a steam generator, but the generator does not exhaust the steam when you turn it off, you’ll need to manually drain the generator at the end of each day. This will help draw off sediments and impurities in the water and keep the generator clean.
  • Maintain detailed autoclave log sheets, noting the contents of the load, cycle type, and so on for each cycle you run. In addition to ensuring that each cycle meets the appropriate sterilization standards, keeping log sheets also creates a paper trail for maintenance purposes. You can download a free log sheet template here.


  • Flush the chamber with clean, non-chlorinated water or chamber cleaning solution. This is especially important if you routinely sterilize saline solutions. Depending the types of goods you sterilize, you may also need to do a scrub cleaning on a regular basis.
  • Inspect the door gasket for tearing, pitting or warping. If you see any of these, it may be time to replace it — in which case, you’ll want to contact your maintenance provider to schedule professional service.
  • Visually check for water and/or steam leaks. If you see a leak, identify the root cause and call in a professional for repairs as soon as possible.

Every 300 Cycles

  • If applicable, confirm that the vacuum pump contactor is operating properly during cycle testing and replace as needed.
  • For hinged door autoclaves, add a small amount of high temperature lithium grease to the door hub’s oil port and turn the door handles back and forth to work the grease in.
  • Replace printer paper and ribbon.
  • Inspect solenoid valves for leaks and replace any leaking valves.
  • If applicable, inspect air filter assembly. If the air filter is wet, there are signs of rust on the housing, or if the chamber vacuum will not release at the end of a cycle, replace the entire assembly using a vacuum release valve repair kit, spring check valve, and new air filter. If the unit is equipped with a vacuum breaker, check for leaks, weeping, or if the chamber is not releasing vacuum.
  • any damage that may have been caused by overheating or excessive wear. Damage to the power cord can pose a fire hazard, so if you notice any damage, contact your maintenance provider.

See Our Full Library of Autoclave Self-Service Instructional Videos >>

Q.  What Is the Process for Cleaning an Autoclave?

A. Cleaning an autoclave is a relatively simple. Here’s a step-by-step breakdown of the process:

  1. Make sure that the steam to the jacket is off. You want to wait until the autoclave chamber has cooled off a bit. A warm chamber is OK.
  2. Pour C3 cleaner (included in CSS’s C3 Chamber Cleaner starter kit) into the autoclave chamber.
  3. Wipe down the interior of the chamber using cleaning pads (also included in our C3 Chamber Cleaner starter kit) and scrub as needed.
  4. Wipe out the chamber with a damp cloth to remove excess residue or rinse with cold, distilled water.
  5. Repeat this process as necessary.

Q. How Often Should I Have a Professional Inspect My Steam Autoclave?

A.  Planned maintenance inspections that are part of a preventative maintenance (PM) plan typically occur based on elapsed time (i.e., quarterly, annually, etc.).  Although this is generally seen as Good Service Practice (GSP), it may also be worth initiating service inspections based on actual usage — say, every 300 cycles — versus time alone.

For example, you may have an autoclave that runs only once per week and is turned off in between runs. In this case, the unit only sees approximately 50 cycles in one year and may not even require an annual inspection. By contrast, if you have unit that runs six cycles per day, five days a week, then a quarterly inspection is probably best.

Discover the 53 Items Every Autoclave Maintenance Plan Should Include >>

Q.  What Are the Leading Causes of Steam Autoclave Damage?

A. Aside from usage, environmental factors can significantly impact equipment longevity and the frequency with which inspections should occur. Chief among these environmental factors are steam and water quality.

It’s imperative that you feed saturated steam with acceptable dryness and particulate levels into your autoclave because particulates can damage valves and cause steam traps to fail prematurely.

As far as water quality is concerned, hard water in the form of calcium carbonate can cause scale buildup on heating elements, plumbing components, and sterilizer surfaces. Scaling decreases the efficiency of the heating elements significantly, causing components to work harder, which reduces their life expectancy. Chlorides in the water source can be particularly damaging (even to high-quality stainless steel) and can lead to corrosion, pitting, and other types of damage to the metal.

Learn More About the Impact of Poor Water Quality >>

Q. Which Steam Autoclave Components Should I Be Most Aware of When It Comes to Routine Maintenance?

A. The following steam autoclave components should be carefully monitored:


There are two primary types of automatic valves used: Valves for steam and valves for other applications like air, water and exhaust. Typically the steam valves will wear quicker than other valves.  Steam to jacket valves see the most use as most jackets remain at temperature while awaiting the next sterilization load. Thus the jacket valve is consistently pulsing while maintaining the appropriate temperature/pressure in the jacket. Manual valves like ball valves and needle valves will typically last the life of the stream autoclave.

Heating Coils

Steam autoclave life is highly dependent on incoming water quality and maintenance—particularly water hardness, frequency of blow-downs (draining the generator of water and flushing out deposits), and any descaling procedures performed. With proper boiler maintenance and attention to water quality, heating coils should last five to ten years on average, although decreasing efficiency and performance may be experienced. Depending on water quality, and the number of cycles run, it is recommended to blowdown the generator daily or weekly.


Contactors are basically high amperage electrical relays and are used on sterilizers equipped with electric steam generators and liquid ring pumps. Switching a high voltage connection on and off is a very demanding function and causes significant wear on the contactors. It is vital to ensure that all high voltage wires are periodically tightened as thermal cycling can cause them to loosen over time. Contactors should be regularly inspected and replaced when there are signs of pitting, heat damage, or excessive arcing on the points. The life of the contactors will depend greatly on the amount of use the sterilizer sees.

Steam Traps

Steam traps are heavily dependent on the quality of the steam delivery system and absence of debris. For facility-supplied steam, a steam trap inspection program should extend beyond the sterilizer to include all of the traps back to the boiler. Although various types of traps can be used in a steam delivery system/steam autoclave, they all perform the same function–removing condensate while allowing the passage of dry steam.

Safety Valves

Per the ASME pressure vessel standards, safety valves are calibrated and set to be equal to or less than the maximum allowable working pressure (MAWP) of the chamber and/or jacket, depending on sterilizer manufacturer. The MAWP will be shown on the stamped vessel plate visibly located somewhere on the vessel exterior. This is the final fail-safe device for the pressure vessel should all electronic controls fail. Therefore, it is imperative that the safety valve is inspected, tested and verified to be in proper working condition based on the recommendation of the sterilizer and/or valve manufacturer as well as local inspection and insurance agencies. It is common practice to inspect and test safety valves on a regular basis.


The controls should last the lifetime of the device assuming they are protected from excessive heat, humidity, and electrical noise/surges/spikes. Particularly, PLC controls have proven to be extremely reliable across industries and in various environments. Although devices vary, in most cases the backup battery should be replaced every 3-5 years to avoid loss of memory or programs. The electrical connections should be covered or within an enclosure to avoid direct contact with water, steam (when the door is opened, for instance), or vapor from the drain or other devices in the same area. Items like control screens may be located above the chamber door provided they are adequately protected from heat and excessive moisture. In rare cases where software updates are required, modern controls can typically be updated via laptop software, USB port, or remotely via an internet/Ethernet connection.

Vacuum Pump (Pre-Vacuum Units Only)

Vacuum pumps should last the lifetime of the steam autoclave. Hard water can cause a build-up to occur within the pump decreasing efficiency and placing greater strain on the motor and impeller. It is possible for the impeller to become nicked by debris that passes through the strainer and the impeller can become imbalanced. Monitor solid goods such as animal bedding that can be drawn through the drain by ensuring that the chamber drain strainer is clean and in good condition. Occasionally, pump bearings will wear depending on usage. If pump maintenance is needed, trained service technicians can often easily clean the pump head and replace worn components.

Download Our Free Steam Autoclave Maintenance eBook >>

To help you and your facility easily remember which common autoclave components to inspect during preventative maintenance, use the table below as your guide:

Table 1            Common Autoclave Components to Inspect During PM’s

Component Comments
Valves (Steam) Steam causes valves to require maintenance more often than air, water or exhaust.
Valves (Air) May not require replacement but should be inspected.
Heating Coils Water quality and ongoing maintenance, including blow-down, can affect longevity.
Steam Traps May not require replacement but should be inspected.
Contactors Replacement will depend greatly on usage.
Safety Valves Replace as recommended by local regulatory authorities; may only require testing or inspection.
Controls When protected from excessive heat and moisture, should last the life of the unit.
Vacuum pump Under normal circumstances and loads should last the life of the unit.
Door Lock Assembly On hinged door autoclaves, check the door locking mechanism. May not require replacement but should be inspected.

Q: What Service Plans Does Consolidated Sterilizer Systems Offer?

A: We offer two SterilCARE™ plans:

  • The Safety Plus plan includes an annual inspection, annual safety component replacement, and annual PM component replacement and comes with a Safety Pax preventative maintenance parts kit.
  • The Proactive plan includes an inspection for every 300 cycles and annual safety component replacement. PM components are replaced with every inspection, and the plan comes with a PartsPAX™. Please note that which PartsPAX™ kit you receive will depend upon your frequency of service.

We also offer a customized service program option, which can be configured based on your specific facility requirements.

Q: What Are PartsPAX™ Kits?

A: PartsPAX™ are preventative maintenance parts kits, which are included in our SterilCARE™ service plans or can be purchased separately. We currently offer three PartsPAX™ kits:

  • The Safety Pax kit includes a C3 Chamber Cleaner starter kit, door sealant, internal lock assembly, a door gasket, a jacket safety valve, a chamber safety valve, door lubricant, a generator safety valve, and a contactor.
  • The Performance Pax kit includes a valve assembly kit (chamber, jacket, exhaust, water, gasket air, gasket exhaust), a vacuum release assembly kit (valve repair kit, air filter, check valve), a contactor, a water fill valve repair kit, sight glass with gasket and valves, and a generator flange O-ring.
  • The Complete Pax kit includes all of the parts and components featured in both the Safety Pax and Performance Pax kits.

At CSS, we offer a full range of preventative maintenance plans and parts kits. We also support full-service steam autoclave maintenance through our steam autoclave service and maintenance department, complete with field engineers and technicians.

Contact CSS today to learn more. We have a team of sterilizations specialists who can help you avoid unnecessary equipment failures, autoclave downtime, and costly repairs.

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Preventative and proactive maintenance are the keys to reducing downtime and ensuring the longevity of your autoclave. Read this eBook to learn how to properly maintain your autoclave and develop a comprehensive maintenance plan.

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