Whether in a university or hospital, lab refrigerator and freezer maintenance should be regularly carried out for maximum efficiency. Nowadays, functioning cold storage units are essential for preserving safety, cost-efficiency and quality assurance. For example: the COVID-19 vaccine can only maintain efficacy within ultra-low temperature (ULT) freezers. In order to ensure consistent, adequately low temperatures, this vital lab equipment require maintenance and calibration.

Usually, it’s best to leave ultra-low temperature (ULT) freezer repairs and maintenance to factory-trained technicians. However, there are a few easy steps you can take towards preventative maintenance. In this post, we’ll outline four of them.

This post has been updated for accuracy. The original post date is June 25th, 2019.

Top 4 Best Practices for Lab Freezers & Refrigerators

These units contain irreplaceable samples. Furthermore, those samples can contain years of research, which can be invaluable. Regular maintenance on your freezers and refrigerators will provide many years of reliable service.

1. Keep the Interior Stocked

All freezers and refrigerators work the best when they are stocked. Empty lab units may result in large temperature fluctuations. Therefore, to avoid this, we recommend keeping your units at least 30% full.

There are times where you will not be able to stock your lab’s ULT freezer to 30% full. A possible solution to this is to add water bottles or freezer gel packs to help stabilize the interior. In addition, it’s equally important to not overfill the unit. Air must be able to flow freely.

2. Clean Refrigerator and Freezer Door Gaskets

A gasket’s purpose is to form a tight seal around the edge of the door. Freezer and refrigerator gaskets are necessary to stop warm air from entering, or cold air from leaving. Therefore, keeping them clean is essential to maintaining your laboratory equipment.

Regularly checking and cleaning your refrigerator gaskets will help maintain the units performance. Your unit should be checked for leaks, and cleaned by wiping them down with a cloth. Dust and dirt can lead to ULT freezer failure by loosening a once-tight seal.


Portrait of a female researcher researcher taking a substance from a freezer

Quick Tip:

3 Easy Ways to Check Freezer Door Seal

  1. Check for cold air by running your hand along the outer edges. If you feel cold air or there is an accumulation of ice, then you need to replace your gaskets.
  2. Leave a flashlight on inside the freezer and shut the door. If any light escapes, then the gasket is not functioning properly.
  3. Place a piece of paper or dollar bill between the freezer and the closed door. If you can move it, then the gasket is not sealing.


3. Monitor Freezer & Refrigerator Temperatures

Most medical freezers and refrigerators have designated spaces for monitoring equipment. These are generally the best areas to test the temperature from. If you are adding your own probes, it is important for them to be placed properly. For an accurate reading, probes should be placed in the center of the unit.

Additionally, Ultra-Low Freezers have alarms to alert you of temperature issues. This includes high temps, low temps, power failure, door being left open, and more. It is important to not ignore these alarms, even though they can usually be muted.

4. Utilize a ULT Freezer Service Agreement

Day to day operations at a lab can be hectic. It may not be possible for you and your staff to commit to regular maintenance checks and cleaning of you freezer or refrigerator units. A customized service agreement from Cryostar Industries can be customized to suit your needs.

Our sales staff can do a walk-through of your facility and outline an agreement that will help protect your investment for years to come. We offer several options that range from basic preventative maintenance to full-service agreement.



Temperature-sensitive materials in labs requires reliable, long-term cold storage. When choosing a refrigerator or ULT freezer, many labs overlook the importance of maintaining it long term. However, failure to maintain a ULT Freezer can result in poor performance. This will be detrimental to the unit and, moreover, your lab samples.

Young male scientist and laboratory freezer
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