Role of the Speaker of the House
From Wikipedia: The Speaker of the House is the presiding officer of the United States House of Representatives. The office was established in 1789 by Article I, Section 2 of the United States Constitution. The Speaker is the political and parliamentary leader of the House of Representatives, and is simultaneously the House's presiding officer, leader of the body's majority party, and the institution's administrative head. Speakers also perform various other administrative and procedural functions, and represent their congressional district. Given these several roles and responsibilities, the Speaker usually does not personally preside over debates. That duty is instead delegated to members of the House from the majority party. Neither does the Speaker regularly participate in floor debates or vote.
The Speaker and Roll Call
As noted above, the Speaker does not regularly vote. Roll Call tallies do not include the Speaker when he or she does not vote.