The executive committee of the Washington Teacher's Union recommended unanimously last night that striking teachers return to work today, a decision virtually certain to end their 23-day-old walkout.

The committee's action came serveral hours after a D.C. Superior Court judge met a key union demand and reinstated unitl July 15 the union's old contract with the school board while negotiations continue on a new agreement.

"We have achieved our objectives," union president William H. Sions declared exultantly follwoing the executive committee decision. "Now teachers can return to work under the contract with dignity and professional respect."

A general membership meeting of the union was scheduled for 7:30 a.m. today at McKinley High School. Simons said he was confident teachers would vote then to return to work and would be back in their classrooms by 10 a.m.

The strike, which has been the city's longest teacher's walkout ever, started March 6 after the school board refused to extend the old contract for a fourth time, contending that it was too prounion.

But yesterday, in reinstating the pact for about 3 1/2 months, D.C. Superior Court Judge **gladys Kessler made and emotional appeal for a truce between the union and the school board.

"The school children of this city find themselves pawns in a dispute over which they have no control," Kessler said after she read her new order. "The public interest cries out for the opening of the schools. . . It is time 3 1/2 long weeks. It is time for this dispute to end."

Kessler acted yesterday in response to a request by Mayor Marion Barry that the old union contract be extended until mid-September.

School board lawyers strongly opposed Barry's motion as "capitulating" to union demands. Following the ruling, the board's vice president, Carol Schwartz, remarked, "now it appears that everybody except the board of education is running the public schools."

On learning of the union leader's recommendation last night, Board President Minnie S. Woodson said she still felt "watchful and not too confident."

"I'm not sure it's over yet," Woodson said, "When I see tearchers back in the classroom, then I'll believe they're really back.

"If the judge's decision was a good one," she added, "we'll see what happens at the negotiating table. The real work is before us now."

Board member R. Calvin Lockridge urged an appeal against Kessler's ruling, and a meeting was scheduled for 12:30 p.m. today to discuss the board's next step.

"We're not concerned about the board's position," Simons remarked last night. "If they care to lock out teachers, that's their problem."

"We will put this "[strike] behind us and hope to heal the wounds," the union president added. "We want to begin moving toward putting the system back together again."

Simons told reporters he thought there were no winners or losers in the long strike. But a union official standing near him remarked that the message of the strike was clear: "Don't mess with Bill [Simons]. Don'tmess with teachers in Washington, because we will come and get thee."

In announcing her order, Kessler said she was dealing with the "practical realities" that the strike hd become "bitter and simply gotten out of hand," even though she twice previously had declared the walkout illegal and ordered teachers to return to their classroom.

In a back-to-work order last Saturday, Kessler reinstated the old contract for one week. But at a mass meeting the next day teachers voted to defy the order because the contract extension was not long enough.

Yesterday Kessler said a one-week reinstatement of the contract was "simply too short a time for the parties. . .to even reach a framework for resolving their disagreement s after so protracted a dispute."

Under her new order, Kessler said that all unresolved issues in the contract dispute must be turned over to a three-member fact-fining panel, with one member appointed by each side and with an impartial chairman. She said the panel must make recommendations for a new long-term contract by June 15, the last day of the current school year.

Panel's recommendations, which are not binding would be the basis for new contract talks, but Kessler said she expected a final agreement to be signed before the fall school term starts in early September.

Last night Simons said he was confident that timetable would be met.

Until July 15, Kessler said the school board could take "no adverse action" against any teacher for participating in the strike. She said the issue of disciplining teachers should be disposed of at the bargaining table or "through existing procedures."

During 2 1/2 hours of hearings yesterday, Kessler also heard arguments by school board lawyers that she should begin collecting immediately the fines she imposed against the teacher's union and its leaders for violating her contempt order of March 12.

Board lawyers said the fines now total almost $1 million. By last evening Kessler issued no ruling on the fines yesterday, but her office indicated she may do so todya.

Mayor Barry, who had filed a motion seeking a long-term extension of the contract after his previous effots to end the strike had failed, issued a statement early last night, saying he was "very pleased and grateful" for Kessler's new order.

Now I hope and expect that the union and board will exercise common good judgement, and accept the judge's order, thus ending the strike for the benefit of the entire city, particularly the 113,000 children whose education has been so drastically interrupted. . ."

On Tuesday night shortly after the mayor made his court motion, union locas representing about 5,000 school custodians, cafetaria workers and toher nonteaching employes voted to delay a work stoppage in support of the teachers, which had been planned for yesterday morning.

After she issued her new order, Judge Kessler said she was acting partly to "forestall and avoid" strike action by othe school system employes that "would widen the conflict and worsen it.

"That would close the public schools and would bring to a halt what public education now is taking place," she said. "[The city] needs a fully operative school system with teachers teaching and students learning."

Schools have remained open ever since the strike began.

According to school board figures, almost half the city's mor than 6,000 teachers have been reporting to work for the past two weeks, but School Superintendent Vincent Reed said the walkout has had a "devastating" effect. Yesterday, the shool board reported, only 40 percent of ther city's 113,000 students were in class.

The board had sought major changes in the old union pact, which it said gave the teacher's union excessive power to shape school policy and limit the authority of principals.

But the union never retreated from its position that its members would return to work only if the old contract was reinstated.

Before Keslerruled yesterday, school board layer George Margolies arguesd that Barry's suggestion for a long-term extension of the pact would amount to "rewarding the union" for defying previous back-to-work injunctions.

Union lawyer William Peer told the judge the union had no objection to Barry's porposal, but would prefer a new contract, lasting until August 1980.

Beginning next January, the school board will gain the authority to negotiatt teachers' pay. At present it only has power to establish school polices and working conditions.