Harvard has filed suit in Middlesex County court alleging that a plumbing company overcharged the University more than $100,000 for work it did in the renovations of the biology laboratories between 1983 and 1988.

The company, Maurer and Sforza, Inc. of Natick, Mass., had begun to pay back its debt to Harvard, but then stopped. The suit, entered last month, seeks to recover $40,000 still owed to the University.

According to the December 24 suit, Maurer and Sforza were hired as part of the $30 million dollar reconstruction project. The plumbers were paid approximately $2.2 million.

Alfred Maurer, the president, and John Sforza, who is treasurer and clerk, were also named as defendants in the complaint.

A response by the defense is expected by January 28. Maurer refused to comment, referring questions to Boston attorney Joseph Corwin. Corwin did not return a phone call yesterday.

Harvard's Internal Audit Department audited Maurer and Sforza's work and found that the plumbers had overcharged Harvard more than $100,000, University Attorney Frank J. Connors charged in the suit.

The two groups had a series of discussions and drew up a "Settlement Agreement" on November 21, 1990.

In the agreement, Maurer and Sforza agreed to pay the University $50,000 as compensation for the overcharges. They made an initial payment of $5,000 and were to pay the rest in installments to run through November 1, 1995.

The agreement called for five payments which increased from $5,000 to $12,000 and were due in the beginning of every November through 1995.

The plumbers made their first payment in 1991 as scheduled, but have continued to default on further payments even after Harvard granted them a one year extension.

In all, the complaint says, the plumbers have paid Harvard $10,000 of $50,000 they owe under the Settlement Agreement.

The Harvard complaint charges, "that Maurer & Sforza has reconsidered the wisdom of the Settlement Agreement and does not intend to make future payments as provided in the agreement."