Have you ever wondered, ‘why do I need to defrost my freezer?’
If you own a manual defrost freezer, and you want it to continue working optimally, you will need to defrost it since ice will build up on the inside of the unit. Unlike Auto-defrost freezers with a warming compressor system, Manual-defrost freezers maintain a more constant temperature, and they do not go through varying cycles of warm and cold.
You might ask yourself, ‘why anyone would want a Manual-defrost freezer, which requires periodically defrosting the unit, when the Auto-defrost would do all of this for you?’ The answer lies in temperature stability and uniformity. To melt any ice build-up, auto-defrost freezers experience an increase in temperature (often above freezing), which results in a wide temperature fluctuation inside the cabinet. If you require tight temperature control in your freezer (when storing vaccines or enzymes, for example) then a manual defrost unit is what you need
You might also be wondering ‘if ice is below freezing temperatures how could ice build up in a freezer be detrimental?’ Surprisingly, ice build up actually causes internal temperatures to rise. A manual defrost freezer with a significant build-up (about 1/8”) creates an ‘igloo effect’, with the ice insulating the interior of the unit, slowly raising the temperature of the freezer and your samples. The compressor will need to work harder to try to keep the temperatures at the set-point, causing stress on the compressors as well, and this can ultimately lead to complete unit failure. Defrosting your manual defrost freezer, therefore, is hugely important.
The defrosting process is a fairly simple process. You should allow a full day to complete this process, and arrange for your samples to be moved into a Back-up freezer while this is happening. We have outlined this defrosting process in full here.