Seattle teachers will vote Tuesday afternoon on a tentative contract agreement announced Sunday by Seattle Superintendent José Banda and Seattle Education Association President Jonathan Knapp.

Banda and Knapp said the two sides settled on the agreement early Sunday morning.

Banda did not include any details about the agreement in a news release, saying the membership of the Seattle Education Association still needed to ratify it. The union has scheduled a general membership meeting for late Tuesday afternoon at Benaroya Hall.

If teachers approve the agreement, school can start as scheduled Wednesday for the more than 50,000 students projected to enroll this year.

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Knapp said union leaders would not be releasing details of the agreement.

“That’s for our membership to have a first look at and for them to decide,” he said. The union has 5,000 members including teachers and classroom aides.

Knapp said he has scheduled meetings of the union’s board and representative assembly Monday, which will be followed by the membership meeting Tuesday.

The teachers voted down a contract offer from the district a week ago, and the union and the district remained at odds on a number of issues — everything from teacher pay to the length of the school day for elementary teachers.

On Friday, both sides in the negotiations agreed to bring in a mediator from the Public Employment Relations Commission. Knapp said the two sides were finding it difficult to agree on some of the issues.

One of the biggest issues was the use of test scores in teacher evaluations. The union wanted to suspend the use of the scores in evaluations, so that the district and union can jointly work out a better way to do so.

The union said the current method was outdated for a number of reasons, including the fact that Washington students soon will be taking a new set of tests.

The district acknowledged such changes are on the horizon, but it didn’t want to stop using test scores in the meantime.

Another issue was on extending the official workday of elementary-school teachers, which is 30 minutes shorter than that of middle- and high-school teachers, and of elementary teachers in other districts.

The district had earlier withdrawn a proposal that union leaders said was the most problematic — one that would have raised the limit on the number of students that could be in classes from grades 4-12 before the teacher would receive either extra pay or additional help from a classroom aide.