Employes at Save Right, the new Giant Food warehouse store in Northeast Washington, voted 7-1 Wednesday night for a union contract that will permit the chain to pay them less than workers at conventional Giant, Safeway and Grand Union supermarkets.

Under the contract, the difference in pay can be as much as $1.69 an hour, or roughly $3,500 a year. For example, a clerk in the warehouse store would be paid $8 an hour compared with $9.69 for a clerk at a conventional supermarket.

The lower warehouse wage scale already is in effect for 600 to 700 workers at seven local Grand Union Basics stores and six Safeway Food Barns in keeping with agreements between the chain supermarkets and United Food and Commercial Workers Local 400.

Supermarket officials say that they can charge lower prices at warehouse stores because they pay lower wages there. Thomas R. McNutt, president of Local 400, said the union agreed to lower wages because it saved hundreds of jobs that would have been lost if the chains had closed their borderline stores rather than convert them to warehouse operations.

He also said that the gap in the two wage scales could be narrowed during future contract negotiations.

About 40 persons now work at the Save Right store. Prior to the vote on the union contract, they were being paid nonunion wages, which were less than the union scale for warehouse store workers.