Arlington Republicans last night overwhelmingly nominated Robert E. Harrington to run as their candidate in the County Board race this fall.

Harrington, a retired Air Force colonel and the former business manager of St. Agnes Episcopal Girls School in Alexandria, got 437 votes -- almost 60 percent of the ballots cast in the party's canvass--a party-run primary.

Harrington will face two-term incumbent Ellen M. Bozman in the Nov. 3 election. Bozman is running as an independent with the endorsement of county Democrats and the nonpartisan organization, Arlingtonians for a Better County.

In winning the canvass, Harrington outpolled Jim M. Wright and Roger S. Morton, both federal employes who plan to run as independents and hoped to get the GOP endorsement. Wright got 257 votes and Morton 68. The Hatch Act prohibits federal employes from running for office as party nominees.

Last night, Harrington told nearly 200 cheering Republicans assembled at the Lyon Village Community House, where the balloting took place: "I do not believe in an expensive bureaucracy. I do not believe in higher taxes and I do not believe in higher expenses and continuous increases in the budget which means more money out of the taxpayer's pocket."

Harrington was endorsed by Republican County Board Member Walter L. Frankland and GOP School Board Chairman Claude M. Hilton. County Board Chairman Stephen H. Detwiler had endorsed Wright.