The $7.6 million Prince William County administration complex has incurred its first cost overrun, according to Deputy County Executive Rick Noble.

The county issued a change order of $62,161 in the Centex Construction Co.'s contract to build the complex on Davis Ford Road. Although the original estimate for the complex was $6.1 million, more than $1 million was added to the cost early this year when the county won its bid for the Prince William Pirates baseball franchise, a Pittsburgh Pirates farm club, and decided to add a professional ballpark and parking to the construction site.

The overrun is attributed to an inadequate design for the cooling system in the computer room, Noble said. Because there will be more computers than originally planned, the extra cooling equipment will be bought and installed at a cost of $59,764.

Other added costs in the change order, the fourth since the project began, will pay for larger telephone conduits to replace the ones in the original plan. The cost of the change will be $2,237.

Also, the county reimbursed Centex for construction permits that the company had paid for when the project began in January.

The supervisors must approve any change order over $5,000. Said Chairman Kathleen Seefeldt, "We've built schools, a senior citizens center, a courthouse and a jail in this county in the last few years and there's never been this kind of a fuss over a change order. We don't feel the staff has let us down just because we had to change gears."

The building is "right on schedule," Noble said, and it is slated for completion in mid-1985.

Next summer the county will seek bids for the second phase of the administration complex, a $3.5 million structure that will house several agencies. County employes are scattered at sites in Manassas, including one on Sudley Road, one on Mosby Drive and the county building on Lee Avenue.

Because the county runs the offices on Sudley and Mosby, the new complex will eventually save the county money, Noble said.