Written and maintained by CASRAI Editorial Board
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This page describes products and general use; it is not medical advice. It is a general reference. For any specific unit, the manufacturer’s own manual or service procedure governs.
Who uses it: lab managers, clinic and dental sterilization staff, and technicians who maintain steam sterilizers (autoclaves) and need to recognise a worn door gasket and understand what a correct replacement involves.
What an autoclave gasket is
An autoclave gasket is the flexible sealing ring that sits in a groove around the door of a steam sterilizer. Its job is to seal the chamber when the door is closed. One manufacturer’s self-help sheet states the consequence plainly: if the door gasket is not perfectly smooth, it will not seal the chamber properly.
The gasket is a wear part. Because it is the one component pressed against the door every cycle, it is the first place to look when a unit leaks steam at the door. For wider fault-finding, see the guide to common autoclave problems and fixes.
How it seals and how it is fitted
On the models covered by the manufacturer documents listed under Sources, the gasket is not glued or bolted in. It is pressed into a groove in the door and held there by the groove walls, with a thin film of silicone lubricant on the groove walls to ease fitting. That is why fitting technique matters: a gasket that is lumpy, wavy or partly out of its groove cannot seat evenly around the whole door.
Types and variants
Gaskets are model-specific. The Tuttnauer procedure names part numbers for the Elara 11, and the Covetrus sheet is written for the EZ9Plus and EZ11Plus only. The groove, shape and fitting sequence differ between models. A gasket that suits one autoclave should not be assumed to suit another; the unit’s manual or the manufacturer’s service documentation is the reference for the correct part.
Two manufacturer procedures compared
| Point | Covetrus EZ9Plus / EZ11Plus self-help sheet | Tuttnauer Elara 11 installation procedure |
|---|---|---|
| Unit state | Replace while the autoclave and its door are cold, to avoid injuries. | Not stated as a temperature rule; the procedure requires the unit to be switched on while the door cover is removed. |
| Door plate | Not mentioned. | Mandatory to remove the door plate; failure to do so distorts the gasket and causes leakage. |
| Groove cleaning | Remove remnants of the old gasket with a plastic scraper and plain water as needed. | Clear the groove with a material suitable for cleaning the chamber; plain water is also an option. |
| Lubricant | Small amount of silicone lubricant on both groove walls; a silicone-based product is required (it names Würth Silicone Lubricant and Dow Corning 111). | Silicone grease on both groove walls. |
| Seating order | Press in top and bottom, then left and right, then the points in between; smooth all the way round. | With the door plate flat on a table, divide the door into eight sections and set sections 1 and 5, then 3 and 7, then 2 and 6, then 4 and 8. |
| Final check | Gasket must sit evenly without waves, humps or cavities. | Gasket must be straight and not wavy; run a short cycle and verify there are no leaks. |
Source: Covetrus document P054700G and the Tuttnauer Elara 11 door gasket installation procedure (both listed under Sources). The comparison shows what two makers agree on, not a universal procedure.
How to choose the right replacement
The sources point to one rule: use the replacement specified for your model. The Tuttnauer procedure lists the exact gasket and silicone grease part numbers for the Elara 11, and the Covetrus sheet is written for the EZ9Plus and EZ11Plus only. Before fitting anything, identify the unit’s model from its data plate and read the manual’s gasket section, including whether the door plate must come off first.
Inspecting and replacing safely
What to look for
A 2014 distributor care article reposted on MedWrench (secondary context, not a standard) recommends inspecting the door gasket daily for excessive wear or cracking, and cleaning the gasket and its mating surface with a mild detergent. It says annual preventive maintenance would normally include replacing wear parts such as gaskets, seals and filters, and gives no fixed replacement interval. Follow the interval and inspection criteria in your unit’s manual. Related checklists: autoclave preventive maintenance checklist and when to replace an autoclave.
What the manufacturers state about replacement
- Covetrus says to replace the gasket while the autoclave and door are cold, to avoid injuries. The Tuttnauer procedure instead requires the unit to be switched on while the door cover is removed.
- Read the model’s own procedure first. On the Elara 11 the door plate must be removed; skipping it distorts the gasket.
- Covetrus: remove remnants of the old gasket from the groove with a plastic scraper and plain water as needed.
- Apply a small amount of silicone lubricant to both groove walls.
- Seat the gasket in stages, then smooth it all the way round.
- After fitting, confirm there are no leaks by running a short cycle (Tuttnauer).
The step order and the parts to remove differ by model, so treat the list above as a summary of what both makers state, not as a replacement for the manual.
Common mistakes
- Too little lubricant. Both makers warn that replacing the gasket becomes difficult.
- Too much lubricant. Both makers warn that the gasket will spring out of the groove.
- Leaving waves, humps or cavities. Covetrus states an uneven gasket will not seal the chamber properly.
- Not removing the door plate where the model requires it. Tuttnauer states this distorts the gasket and causes leakage.
- Skipping the leak check. Tuttnauer asks for a short cycle after replacement to verify no leaks.
FAQ
What does an autoclave gasket do?
It seals the chamber against the door. If it is uneven or damaged, the chamber will not seal properly.
Can I use any silicone product to fit it?
Use what your manual specifies. Covetrus requires a silicone-based lubricant and names Würth Silicone Lubricant and Dow Corning 111 for its units; Tuttnauer lists a specific silicone grease part number for the Elara 11.
How often should it be replaced?
The two manufacturer procedures cited here give no replacement interval. Inspect it regularly for wear and cracking and follow the interval in your unit’s manual or service plan.
Is one gasket interchangeable between models?
Do not assume so. Both procedures are written for specific models, and the Tuttnauer procedure names the part numbers for the Elara 11.
Sources
- Covetrus, EZ9Plus and EZ11Plus “User Self Help: Replacing Door Gasket”, document P054700G, exp.northamerica.covetrus.com, checked 2026-10-30.
- Tuttnauer, Elara 11 door gasket installation procedure, sterilizers.com, checked 2026-10-30.
- “How to care for your autoclave or steam sterilizer”, MedWrench repost (2014) of a distributor article, medwrench.com, secondary context only, checked 2026-10-30.
Related CASRAI guides: what is an autoclave, types of autoclaves.
