Before the bedika, one recites the berakha: “Who sanctified us with His mitzvot and commanded us concerning bi’ur ḥametz” (“asher kideshanu be-mitzvotav ve-tzivanu al bi’ur ḥametz”). Though the actual bi’ur ḥametz will not take place until the following morning with the burning and nullification of ḥametz, we recite “al bi’ur ḥametz” before the search on the night of the 14th, because bedikat ḥametz is the first step in the process of eliminating ḥametz from the home.
One must not speak between the recitation of the berakha and the beginning of the bedika, and if at that point one spoke about matters unrelated to bedikat ḥametz, he disqualified that berakha and must recite another before beginning the bekida. If, however, one talks about unrelated matters after beginning the search, his berakha remains valid, for it applies to the part of the bedika that he already performed. Le-khatḥila one should not talk about unrelated matters during the bedika, so that one maintains focus on the task at hand (SA 432:1; MB ad loc. 5, 6).
One who owns several houses must search them all. He recites the berakha before searching in the first location. He recites it only once, even if the houses are located a distance from one another.
If one must travel, and therefore performed bedikat ḥametz before the 14th of Nisan, even though his search is valid, he does not recite the berakha. One only recites the berakha over a search performed from the night of the 14th onward, because such a search is adjacent to bi’ur ḥametz. Any ḥametz found on the evening of the 14th will be destroyed the next morning. If one was unable to search on the evening of the 14th, and instead searched the following day, or during Pesaḥ, he recites the berakha, because he will immediately destroy any ḥametz he finds, and it is appropriate to recite “al bi’ur ḥametz” over such a search. (Rema 436:1 and BHL ad loc.; MB 435:5).
. The authorities disagree about this, as noted in MB 432:7. According to Pri Ḥadash and Ḥayei Adam, walking a far distance is considered a significant interruption, and he would have to make a new berakha. Conversely, according to Ḥok Yaakov and Ma’amar Mordechai, walking is not considered a significant interruption. This is also the opinion of Kaf Ha-ḥayim 432:22. When in doubt about whether or not to make a berakha, we are lenient. If a homeowner wants to search part of his house and wants to appoint someone else to search the rest of the house on his behalf, he should make sure that the appointee hears his berakha. Be-di’avad, if the appointee did not hear the berakha but it is hard for the homeowner to search the entire house, the appointee should perform the rest of the bedika without a berakha (MB 432:11).
. Indeed according to Ra’ah and Pri Ḥadash, one who is halakhically required to check should make a berakha, since the purpose of the bedika is to ensure that he does not violate bal yera’eh/bal yimatzei afterward; since the Sages decreed that one who leaves his house before the night of the 14th should check before he leaves, he should also make a berakha. According to Ritva and Baḥ, he should make the berakha as long as he checks within the thirty days before Pesaḥ. But Kol Bo and Rema (436:1) are of the opinion that the berakha is also on the burning that takes place the following morning. This is also the opinion of Gra, and seems to be the conclusion of MA, Taz, and others. If one is uncertain about the berakha, we are lenient, and this seems to be the opinion of BHL ad loc.
Itur states that there are those who maintain that one must also make the berakha of “she-heḥeyanu” prior to the bedika, since it is a mitzva that comes periodically, and there are those who say not to recite this berakha. Rosh rules that one should not make this berakha, since the bedika is connected to the Pesaḥ holiday, when anyway he will recite she-heḥeyanu. SA does not even mention the idea of she-heḥeyanu on the bedika. However, some Aḥaronim suggest, as a nice custom, that one take a new fruit or new garment and recite she-heḥeyanu on it before the bedika (Kaf Ha-ḥayim 432:9).