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Refrigerators on Shabbos: Difference between revisions
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Today, manufacturers are introducing new electronic systems into the refrigerator. | Today, manufacturers are introducing new electronic systems into the refrigerator. | ||
The first major problem with refrigerators on Shabbos came with the defrost system. When warm air comes into contact with a cold surface it will condense and stick to the surface- much like a window pane in winter. In freezing temperatures the frost will accumulate and turn into a thick layer of ice. | The first major problem with refrigerators on Shabbos came with the '''defrost system'''. When warm air comes into contact with a cold surface it will condense and stick to the surface- much like a window pane in winter. In freezing temperatures the frost will accumulate and turn into a thick layer of ice. | ||
Inside the freezer walls, manufacturers install a heating coil –like the coils found in a toaster oven- that burns red-hot and melts any frost buildup. (The small amount of excess water is drained into a tray underneath the refrigerator where it evaporates). | Inside the freezer walls, manufacturers install a heating coil –like the coils found in a toaster oven- that burns red-hot and melts any frost buildup. (The small amount of excess water is drained into a tray underneath the refrigerator where it evaporates). | ||
There are three methods used to turn on the defrost coil: | There are three methods used to turn on the defrost coil: | ||
Method 1- Defrost Timers | ''''''Method 1'''- Defrost Timers''' | ||
In older refrigerators (1980), the defrost coil is activated with an internal timer. | In older refrigerators (1980), the defrost coil is activated with an internal timer. | ||
Method 2- Adaptive Defrost | ''''''Method 2'''- Adaptive Defrost''' | ||
Instead of activating the defrost on a timer, a computer calculates the compressor run time only,and then turns it on every few hours for a short period. | Instead of activating the defrost on a timer, a computer calculates the compressor run time only,and then turns it on every few hours for a short period. | ||
This is a real problem to use on Shabbos. If the refrigerator door is opened, hot air that enters causes the temperature to rise and the compressor needs to run longer to keep the food cool. Longer compressor run time means the defrost cycle activates sooner than it would have. | This is a real problem to use on Shabbos. If the refrigerator door is opened, hot air that enters causes the temperature to rise and the compressor needs to run longer to keep the food cool. Longer compressor run time means the defrost cycle activates sooner than it would have. | ||
According to many poskim this is a serious concern. Causing the heating coil to ignite is d’oraysa- a biblical prohibition. The defrost coil is a gacheles shel mateches, which is classified as igniting a flame - havarah . | According to many poskim this is a serious concern. Causing the heating coil to ignite is d’oraysa- a biblical prohibition. The defrost coil is a gacheles shel mateches, which is classified as igniting a flame - havarah . | ||
Method 3- Electromagnetic Sensors | '''Method 3- Electromagnetic Sensors''' | ||
These are usually embedded inside the door and undetectable. they count how many times the door is opened and closed | These are usually embedded inside the door and undetectable. they count how many times the door is opened and closed | ||
The door sensors count the number of times a refrigerator door is opened and closed and activate the coil after a certain number of times. The reason they use this method is that the more the door is opened the more warm air is let in causing ice buildup. So for an example, after 20 times of warm air entering the refrigerator, they estimate, the freezer needs a defrost cycle. | The door sensors count the number of times a refrigerator door is opened and closed and activate the coil after a certain number of times. The reason they use this method is that the more the door is opened the more warm air is let in causing ice buildup. So for an example, after 20 times of warm air entering the refrigerator, they estimate, the freezer needs a defrost cycle. | ||
