Auto-defrost, automatic defrost or self-defrosting is a technique which regularly defrosts the evaporator in a refrigerator or freezer.Appliances using this technique are often called frost free, frostless, or no-frost How to put your Samsung Refrigerator in FORCED DEFROST mode, and other functions. Defrosting the freezer is a task many people are happy to put off as long as possible. Not only does the period between defrost cycles change but also the time duration of the defrost cycle itself. If the freezer temperature is set below 0 o F, you may need to increase your temperature for at least 24 hours. Leaving a freezer that won't defrost for too long may create a bigger problem, so here are some of the most frequent causes for a refrigerator not defrosting. Icing problems, such as icicles forming on the ceiling of a freezer above the unit cooler or around the fan openings of the unit cooler are the result of either too many defrost cycles per day or too long a defrost cycle. The cycle then automatically terminates itself. Check door closure. Refrigerator Normal Run Time. To maintain the efficiency of a manual-defrost freezer, it should be defrosted each time it develops a quarter-inch of ice build-up on the interior walls. How to Easily Test your Defrost Thermostat Video . Do you know how long the defrost cycle typically runs for? They only tell the service techs … Frost building up solely on the back of the freezer section, where the evaporator coil is located, indicates an issue with the defrost cycle. When you have a refrigerator freezer not defrosting properly, there are some troubleshooting items to check out. That side normally runs at about 0 degrees F, but it was around 20 degrees F. I've checked the thermistors and they are good. Here is the thing if the door switch was faulty causing the length of time to be too long between defrost cycles the main board is supposed to recognize that it took too long to defrost and adjust the next defrost cycle to be sooner. 2) With the freezer frozen down, (it must have been running at least a couple of hours to give the contacts in the defrost thermostat a chance to get cold and close) remove the evaporator cover (the cover in the freezer that covers the cooling coil) This is the component that controls how long the heater stays on when the machine is in defrost mode. To put in a brand new defrost timer or simply reinstall the existing one, hook up your green ground wire after which hook up your harness connector. The cycle runs according to a programmed time. Not only does the period between defrost cycles change but also the time duration of the defrost cycle itself.