Common Steam Autoclave Maintenance Questions, Answered

Keeping your 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. To help you with autoclave upkeep, we wrote about the importance of 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 sterilizer 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.

1. What Autoclave Maintenance Options Are Available to Me?

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.

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

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

Daily

• 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.

Weekly

• Flush the chamber with clean, non-chlorinated water or chamber cleaning solution. This is especially important if you routinely sterilize saline solutions. Depending on 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 for a replacement — in which case, you’ll need to contact your maintenance provider to schedule professional service.

• Visually check for water and/or steam leaks. If you notice a leak, identify the root cause if possible and call in a professional for timely repairs.

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 the 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 whether the chamber releases vacuum.
• Check the power cord for any damage that may have been caused by overheating or excessive wear. Power cord damage can pose a fire hazard, so if you notice any, contact your maintenance provider.

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

3. What Is the Process for Cleaning an Autoclave?

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

1. Make sure that the steam to the jacket is turned off. For safety reasons, you should wait until the autoclave chamber has cooled off a bit before beginning. A warm chamber is okay.
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 needed.

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

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 be worth initiating service inspections based on actual usage instead — 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 completes approximately 50 cycles in one year and may not even require an annual inspection. By contrast, if you have a 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 >>

5.  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 >>

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

The following steam autoclave components should be carefully monitored:

Valves

There are two primary types of automatic valves used: valves for steam and valves for other applications like air, water, and exhaust. The steam valves typically wear quicker than other valves. During maintenance:

• Inspect for leaks and wear. Hissing sounds or visible condensation may indicate steam or water leaks around connections.

• Clean valves by removing buildup and debris to prevent blockages.
• Test pressure release valves to ensure they function correctly and avoid dangerous overpressure situations.

Heating Coils

With proper boiler maintenance and attention to water quality, heating coils should last five to 10 years on average, although you may experience decreasing efficiency and performance over time. Depending on water quality, and the number of cycles run, it is recommended to blow down the generator daily or weekly.

During maintenance:

• Look for signs of wear, such as discoloration, cracks, or burn marks, which could indicate overheating or electrical issues.
• If you use hard water, scale buildup can coat the coils, reducing efficiency. Regular descaling and blowdowns (draining the generator of water and flushing out deposits) can help.

• Monitor heating performance. If the autoclave takes longer to heat up or doesn’t reach the correct temperature, the coils may need servicing or replacement.

Contactors

Contactors are high amperage electrical relays that 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, which causes significant wear on the contactors over time.

During maintenance:

• Ensure that all high-voltage wires are periodically tightened, as thermal cycling can cause them to loosen over time.

• Contactors should be inspected and replaced when there are signs of pitting, heat damage, or excessive arcing on the points.
• Listen for unusual noises — A failing contactor may produce buzzing or chattering sounds.
• Use a multimeter to check for continuity and ensure the contactor is operating within the correct voltage and amperage range.

Steam Traps

Steam trap effectiveness is heavily dependent on the quality of the steam delivery system and the presence or 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.

During maintenance:

• Check for signs of steam leaks or excessive moisture in the chamber, which may indicate a failing steam trap.
• Test functionality to verify that the trap is opening and closing correctly.
• Clean or replace clogged traps.
• Keep an eye on pressure and temperature since unexpected fluctuations can be a sign that the steam trap isn’t working properly.

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 the sterilizer manufacturer. 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 confirmed to be in proper working condition on a regular basis.

During maintenance:

• Conduct a pressure release test according to the manufacturer’s recommendations to ensure proper function.

• Check for steam leaks — a constantly leaking valve may indicate wear or improper sealing.

• Replace valves that fail the pressure test or show signs of excessive wear.

• Inspect valves for corrosion and debris, which can prevent them from properly sealing and/or releasing pressure.

Controls

The controls should last the lifetime of the sterilizer — assuming they stay protected from excessive heat; humidity; and electrical noise, surges, or spikes. Particularly, PLC controls have proven to be extremely reliable across industries and in various environments.

During maintenance:

• Verify temperature and pressure readings with external instruments to ensure accuracy.

• Check for any error codes and address them promptly if present.

• Inspect wiring and connections as loose or damaged connections can cause erratic operation or system failures.

• Update software (if applicable) — modern controls can typically be updated via laptop software, USB port, or remotely via an Internet/Ethernet connection.

• Replace the backup battery to avoid memory or program loss (every 3–5 years).

Vacuum Pump (Pre-Vacuum Units Only)

Vacuum pumps should last the lifetime of the steam autoclave. Hard water can cause build-up to occur within the pump, decreasing efficiency and placing greater strain on the motor and impeller.

During maintenance:

• Check the impeller for signs of nicks caused by debris.
• Monitor solid goods, such as animal bedding, that can potentially be drawn through the drain and make sure that the chamber drain strainer is clean and in good condition.
• Inspect pump performance. 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 >>

Door Lock Assembly

On hinged-door autoclaves, the door lock ensures the chamber remains securely sealed during operation. A faulty assembly can lead to adverse events like pressure leaks, incomplete load sterilization, injury, and even catastrophic failure. Regular checks and replacement when needed can help prevent these consequences.

Gaskets

When inspecting your autoclave’s door gaskets:

• Check for cracks, warping, or any brittleness as the presence of these defects can impede the unit’s ability to remain properly sealed during operation.
• If the gaskets are damaged or show signs of wear, replace them to avoid unnecessary downtime.
• If gaskets look to be in good shape, clean them using a damp cloth and mild detergent, avoiding harsh chemicals that can degrade the material.

 

Drain Strainer

The drain strainer catches debris, preventing biohazardous materials, sediment, and other particles from clogging the drain lines. A blocked drain can cause cycle failures or even damage the autoclave.

During maintenance:

• Remove the strainer and flip upside down to remove debris. In cases where large debris is present, you may need to use tweezers for this step.
• Before returning the drain to its place, look it over for cracks or excessive wear.

• Replace if necessary.

Use the table below to help you and your team remember which common autoclave components to inspect during preventative maintenance:

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.
Gaskets	If gaskets are damaged or show signs of wear, replace to avoid downtime. If in good shape, clean with damp cloth and mild detergent.
Drain Strainer	Inspect for cracks or excessive wear; replace if necessary.

7. What Kind of Steam Should I Use in My Autoclave?

Consolidated autoclaves can be configured to utilize your building steam supply or steam from a steam generator. In all, there are four options:

• House steam: In most situations, standard house steam is adequate, if available
• Integral electric steam generator: Typically required when house steam is not available or adequate
• Remote electric steam generator: Steam generated from a boiler that sits adjacent (not integral) to the sterilizer.
• Steam-to-steam generator: Utilized for applications requiring clean steam

The quality of the steam feeding an autoclave is also an important factor in steam sterilization. Steam quality is determined by its measurable physical aspects, such as temperature, dryness, and non-condensable gas content. Deviations from established ranges of these aspects of the steam can result in issues such as:

• Wet loads
• Damaged loads
• Unsterile loads
• Sterilization (biological and chemical) indicator failures
• Staining and corrosion of instruments and containers

8. What Materials Do I Need to Clean My Autoclave?

There are a few basic items you’ll need to clean your sterilizer chamber:

• A specialized cleaning solution like C3 Sterilizer Chamber Cleaner
• Non-chlorinated/purified water, such as reverse osmosis water, deionized water, or bottled water
• A cotton rag or towel
• Cleaning pads
• Autoclave gloves

In terms of specialized cleaning solutions, we recommend using our C3 Sterilizer Chamber Cleaner. This specially formulated cleaning solution is designed to remove rust, scale, and stains from both stainless steel and nickel-clad steel chamber surfaces.

To clean your autoclave, follow the steps outlined in this video:
 

9. What Service Plans Does Consolidated Sterilizer Systems Offer?

We offer two SterilCARE^TM plans:

• The Safety Plus plan includes an annual inspection, annual safety component replacement, and annual PM component replacement. It also 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^TM kit. Please note that the type of PartsPAX^TM 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.

10. 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.