In order to use a dishwasher on Shabbat, the safety switch on the door must be disconnected so that closing the door will not directly turn the machine on. The buyer should check in advance if this is possible and how to do it. For details about the halachic basis of running a dishwasher on Shabbat and for operating instructions, press here.
There are three types of dishwashers on the market: regular, fully integrated, and half integrated. The difference between them is not technological but in the way they are displayed. The integrated dishwasher is behind a wooden door, such that the control panel can be reached only after the door has been opened. Disconnecting the safety switch in such machines will also disconnect the control panel, and therefore these machines can never be used on Shabbat. It is recommended that a fully integrated dishwasher should not be purchased!
Control of the Dishwasher:
Mechanical Program Selection:
Advantage: On a holiday, such a machine can be turned on and off several times by a timer (this can be very important on a holiday which is right before or after Shabbat!).
Disadvantage: An external timer is needed to control the electricity.
In mechanical dishwashers made by Constructa, Siemens, and Bosch, an external switch cannot be used for Shabbat or a holiday, and therefore in these machines it will be necessary to disconnect the door safety switch permanently, both on Shabbat and during the week. This is not good because of safety considerations. (A dishwasher whose safety switch has been disconnected will continue to work even if the door is opened! This is not so serious on Shabbat, when The Zomet Institute recommends that the timer be set for late at night, while the people of the household are asleep.)
Digital Program Selection:
Advantage: Most of these models have their own internal timer so that there is no need for an external Shabbat timer.
Important Things to Know Before Buying a Dishwasher
Digital models that do not have an internal timer must be turned on for a short time before Shabbat starts, and then the Shabbat timer can be used to turn off the electricity. When it goes on again most machines will "remember" the point at which they stopped and continue the washing cycle from there. (Note: There are a few specific models which do not retain a memory of the state before the electricity went off. This should be checked before buying a dishwasher.)
Disadvantage: The machine can only be turned on once, both on Shabbat and on a holiday (see above, Mechanical Program Selection).
For more information and to order service, please contact The Zomet Institute.