Technology has changed drastically over the last 30 years and with that, its application in home appliances, such as refrigerators. What was once merely a question of indirectly activating a compressor on Shabbos, which many leading poskim permitted, is now considerably more complex. Activating the automatic defrost system, which is controlled by microprocessors and door sensors, can involve Shabbos infractions, even if albeit unintentional.
Because of the complexities of these newer appliances, and the uncertainty as to how exactly each one operates, the OU poskim have recommended using a timer when opening the refrigerator door on Shabbos, to avoid any concerns of Shabbos infringement. Rav Belsky zt”l researched this well and was aware of these issues, as is yb”l Rav Schachter Shlit”a. They are both of the opinion that a timer should preferably be used with these newer refrigerators to avoid all questions of chilul Shabbos. The newer the refrigerator, the more complex the question becomes, but even refrigerators manufactured a dozen years ago can still pose significant questions.
As a convenience, an automated timer device is available from Zman Technologies, which was designed under the guidance of Rav Belsky zt”l and yb”l Rav Schachter Shlit”a. The device is OU certified to ensure meticulous Shabbos observance. The device acts like a plug-in Shabbos clock and controls the power to the refrigerator throughout Shabbos based on a preset cycle. When the power is off, the door may be opened and there is no concern of chilul Shabbos. An attached LED green light – red light module indicates when the refrigerator door may be opened. The device maintains a 35 year calendar, so once it is set-up, there is no need to do anything more. It will activate automatically every erev Shabbos and Yomtov.
The device is currently GE certified for use with many GE refrigerators and is still undergoing further evaluation for certification with its newest models as well.