First of all a tremendous yasher koach for being neenah the olam with divrei torah; it is most appreciated. After learning Daf 29, I question the prevalant practice of using a timer to heat a mikvah on Shabbos with cold water that has been "prepared" before Shabbos. Please clarify.

Thank you,

Baruch

The Mishna Berura in O.C. 326-7 Rules that a Mikve on Shabbos may only be luke warm. This is the ruling of the Noda biYehuda that he cites. However he also refers to the Korban Nesanel in Shabbos Chap 2 para. 22 who rules that the Gezerah of washing in hot water did not apply to Immersion in a Mikve.

The Sidrei Tahara Y.D.193 permits immersion for a woman in hot water as does the Birkei Yosef in Y.D.197.

Teshuvos Avnei Nezer O.C. 526 rules that Tevila for a man is also considered a mitzvah and therefore the same Heterim that apply to women apply to men too. He proves this by citing the Rokeach, Sefer haYashar and the Maharil who all permit Tevilah for a Ba'al Keri on Yom Kippur. If it is enough of a mitzva to overide the Issur of washing on Yom Kippur then it can overide the Gezerah of washing in hot water on Shabbos. He emphasizes that one should be careful not to remain in the water for longer than is necessary.

Rav Wosner in Shevet Halevi 5-44 rules that one who observes Tevilas Ezra consistently all year round can be lenient in the winter and immerse in hot water if necessary. Rav Moshe Shternbuch in Teshuvos veHanhagos 1-224 rules that it is permissible to immerse in a hot water mikve on Shabbos.

Rav Moshe Feinstein in the Teshuvos that appear in the appendix to Sefer Hilchos Shabbos by Rav Shimon Eider writes that although people are lenient and permit Tevilah of a Ba'al Keri or Tosefes Kedushah on Shabbos in cold water, it is forbidden in hot water. Even though there are people who do this - it is not proper.

The Paytan says "Tehorim Yirashuha vi'Yekadshuha". May we be blessed to be Tehorim and Mekadshei haShabbos.

Ilan Segal

A Shabbos clock would certainly be no different than any other utensils as far as the Isur of Shevisas Kelim is concerned. There are, however, other concerns raised with regard to their use.

Rav Moshe Feinstein Zt"l, in Igros Moshe O.C.4, 60, writes that if Melacha is done indiscriminately on Shabbos by means of a Shabbos clock this constitutes a Zilusa deShabsa i.e. disrespect to the sanctity of Shabbos. He adds that it is clear to him that had the question of Shabbos clocks arisen in the time of Chazal they would have forbidden their use. He therefore he does not permit a Shabbos clock for anything other than lights. He explains that lights are different as there was a tradition in many places to permit the extinguishing and even lighting of lamps by goyim. (There is some justification for allowing goyim to light lamps for Jewish benefit (Rama O.C. 276 -2), although many poskim protested this practice.) Since switching lights on and off by means of Goyim is an established practice it no longer constitutes a Zilusa deShabsa and is therefore permitted by a Shabbos clock. According to Rav Mosh Feinstein one would not be permitted to use a Shabbos clock for anything other than lights.

The above answer was given in reference to switching on a hotplate by a time switch. When the appliance in question makes a noise there is a further factor to consider.

The Rama O.C. 252-5 rules that preparing a mill before Shabbos to grind on Shabbos is forbidden because of the noise that is made and the consequent disrespect to Shabbos. Any appliance which makes a noise would not be allowed to be operated by a Shabbos clock due to this consideration. Many people rely on more lenient opinions and use Shabbos clocks for other appliances. They should not be used for appliances which make a noise such as radios, washing machines etc.

Ilan Segal