My dishwasher has the option to delay the wash cycle by 3/6/9 hours. Can I load the machine after Friday night meal, close the door, having set the timer Erev Shabat. The water heats up to 55 C, scalding hot. Also a light comes on to show it is operating as the machine is whisper quite.
Any difference for YomTov?
Thank you for your question.
There are a number of issues with setting the dishwasher to run on Shabbos. When the dishes are placed in their respective slots, there can be an issue of borer. When the dishwasher door is closed, it enables the dishwasher to work, which would be “gram bishul” on the water, and “gram havara” on the electricity regarding the heating element when applicable, and a grama on the activation of the machine. An additional issue here is zilzul Shabbos, because it appears that it was turned on Shabbos or Yom Tov. Therefore, the poskim say that it should not be done on Shabbos. Regarding Yom Tov some of the above issue will not apply. However, the zilzul aspect will still apply, that it is an embarrassment to Yom Tov that one’s electric appliances that are usually manually operated, are running on Yom Tov. Additionally, closing the door, is activating the machine via a grama, which would be similar to plugging something into a Shabbos clock on Yom Tov, albeit with a time delay. Therefore you should not set the dishwasher to a Shabbos clock to turn on, not on Shabbos nor on Yom Tov
Be’er Moshe 6 Kuntris Electric 81, Meohr Hashabbos 4 pg. 481, Avnei Yoshpe 3-51(1), Divrei Chachomim 291, Kovetz Halachos (Shabbos) Vol. 1 chapter 4-7, Shemiras Shabbos Khilchoso 12-37 (new edition), Orchos Shabbos Chapter 29-8 ftnt. 24, Poskim.