Why are the Lab Freezer temperature panels not turning solid? L Why are the Lab Freezer temperature panels not turning solid? The PCM inside is NOT below its phase change temperature of -21.5°C/-6.7°F. Make sure that the freezer temperature is always below -30°C/-9.4°F. Post navigationPrevious post: Why are the Fridge Temperature panels (PCM) not turning solid?Next post: Can a regular freezer be used to prep refrigerator temperature panels and store panels? Leave a Reply Cancel replyYou must be logged in to post a comment.