In a major change of command at Washington's third largest bank, Joseph B. Danzansky yesterday was named chairman of the board of National Bank of Washington and Dale L. Jernberg was appointed president and chief executive officer.

The appointments were made by the bank's board late in the afternoon after NBW Chairman Donald Notman resigned "for personal reasons."

Walton W. Sanderson, who had been president and chief administrative officer, was named to a newly created post as vice chairman.

Danzansky announced he will sign as Chairman of Giant Food Inc., effective Dec. 29 but will remain chairman emeritus until Giant's next annual meeting in September.

Notman, Sanderson and Jernberg, who had been executive vice president, had run the National Bank of Washington as a triumvirate for the past five years. The new table of organization puts Jernberg in charge of day-to-day bank operations.

As chairman, Danzansky-the only one of the four who could be reached for comment-said he will limit his activities to chairing board meetings, working on employee relations and aiding in business retention and business development.

Although the major management shakeup produced immediate speculation about difficulties at the bank, Danzansky insisted "the bank is in great shape."

"The whole thing was occasioned by just one move, and that was Mr. Notman's move," Danzansky said, denying that Notman's resignation was requested by the board.

The reorganization apparently was made without the involvement of the United Mine Workers Union, which owns about 70 percent of the stock of NBW.

A UMW public relations man siad he knew nothing of the moves and said the union is not active in management of the bank.

The Mine Workers have received offers from a group of foreign investors to sell the union's shares in the bank, it was learned through sources outside, the union.

Until recently the UMW-which has severe financial problems-has refused to discuss sale of the stock, but two months ago the union agreed to listen to an offer.

The talks are continuing, sources close to the situation said, although Danzansky said he knew of no plans by the Mine Workers to sell.

With assets of $816 million, National Bank of Washington ranks third as among District of Columbia banks, behind Riggs National Bankand American Security.

The bank, however, has been first in earnings growth among major D.C. banks, increasing its profit by an average of 16.7 percent per year over the last five years. The bank's deposit growth, however, dropped below 10 percent last year, less than that of four other banks, according to a study by Johnston, Lemon & Co.

NBW has 23 branches.