The Montgomery County Board of Education, after more than an hour of sharp debate, last night reaffirmed an earlier decision to close two schools in the Potomac area that have day care centers serving more than 100 children.

In its first formal action to reconfirm the school closing and boundary decisions taken last year by the previous board, the board agreed to go ahead with the scheduled closing at the end of this year of Georgetown Hill and Lake Normandy elementary schools.

Working parents whose children attend the day care centers at those schools waged a strenuous campaign over the last month to get the board to consider closing other schools in the area. They accused the board of insensitivity to the impact the closings would have on the children enrolled in the day care programs. They also argued that other day care programs in elementary schools in the area would be overburdened when they get the children from the closed schools.

Parents from Georgetown Hill, the largest of the elementary schools feeding into Churchill High School, said transportation problems would make it impossible for many of the children in day care there to enroll in a program at any other school and that the three schools that planners suggested might be able to pick up Georgetown Hill's day care program wouldn't have enough space.

School Superintendent Edward Andrews argued that the privately operated day care programs are not the legal responsibility of the school board. He said day care programs that operated in schools closed last year have been successfully relocated. School officials said 15 schools closed last year offered day care, and 14 of those programs have been moved to other sites.

In addition, school planners said the program at Georgetown Hill, the largest in the Potomac area, could be housed at either Seven Locks or Beverly Farms elementaries.

The board's actions drew angry outbursts from the audience, composed largely of Georgetown Hill parents. At one point, the audience demanded to hear the board's reasons for not considering closing another school.

The previous board voted to close the two schools last year because of projected enrollment declines. Only one school in the Churchill cluster is more than half full of students.

In its only deviation from actions taken last year, the new board voted to send all Lake Normandy students to Wayside elementary. Andrews had recommended that 49 of those students be sent to Bells Mill elementary.