Warm-Up Cycles for Autoclaves

Sep 16 / Chris Maughan


Warm-up cycles are performed on porous and hard goods load autoclaves to heat the chamber to the working temperature. They are typically done daily, helping the autoclave reach optimal sterilization conditions.

What is a Warm-Up Cycle?

A warm-up cycle is usually the first cycle of the day and is designed to heat both the autoclave chamber and its jacket to the operating temperature. This cycle often has reduced air removal, sterilization, and drying phases, as the primary goal is simply to raise the temperature of the autoclave.

Do You Really Need to Perform a Daily Warm-Up Cycle?

While it's still common practice to perform a daily warm-up cycle, it’s not always necessary. Most modern autoclaves come equipped with a pre-heating phase, where the chamber jacket heats up to its operating temperature before the actual sterilization cycle begins. This pre-conditioning step can often eliminate the need for a separate warm-up cycle.

In some cases, autoclaves are operated with the jacket permanently heated, which also negates the need for a daily warm-up.

Can You Combine a Warm-Up Cycle with a Bowie-Dick Test?

If you’re currently running separate warm-up cycles and Bowie-Dick tests, consider combining them. A Bowie-Dick test cycle will heat the chamber to its operating temperature, making an additional warm-up unnecessary.
Ensure the Bowie-Dick test cycle is set up correctly, with the appropriate air removal and sterilization phases, according to the Bowie-Dick test pack manufacturer's guidance.

How Can a Warm-Up Cycle Help Prevent a Leak Rate Test Failure?

A warm-up cycle can also help prevent a leak rate test failure, particularly if your autoclave chamber contains residual water at the start of the leak test. This issue is common in multicycle autoclaves, especially after performing a liquid load, as condensate can accumulate on the autoclave floor or drain pipework.

If you encounter a failure and suspect water is the culprit, running a warm-up cycle should evaporate any condensate in the chamber or pipework, potentially allowing your leak rate test to pass. If the problem persists, feel free to reach out to me, Chris Maughan, and I’d be happy to assist.
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