The D.C. Rental Accommodations Commission has awarded the tenants of the Farnsboro Apartments, 2129 Florida Ave. NW, a rent rebate, but the residents are appealing the decision. They want a rollback that would decrease their monthly payments and at the same time prevent the landlord from converting the building to condominiums.

The six-story brick building, near Connectivut and Florida avenues, contains 50 units. The tenants are single professionals and elderly people, some of whom have lived in the Fransboro for 20 to 30 years.

In the drive to keep their rents down and to upgrade the physical condition of the building, the Farnsboro tenants have become one of the most active tenants' groups in the city at a time when tenant organizations are increasing in number and becoming more vocal in campaigns against evictions, rent increases and poor maintenance services.

"Our lawyer felt we had grounds for appeal because there were and still are a number of housing code violations outstanding, and by law we are not supposed to receive a rent increase unless the building is in substantial compliance," said Bill Kennard, acting president of the Farnsboro Tenants Association.

City inspectors reported more than 200 violations of the D.C. housing code in March 1977. James Strehle, a Department inspector, said that on a visit to the Farnsboro about a month ago he did not find "any corrections" of the violations. Tenants say the violations range from peeling paint and plaster and cracked windows to running faucets and roach infestation.

Last summer tenants filed a petition with the Rental Accommodations Commission seeking correction of the violations and a rent rollback.

The residents' action came after landlord Lester C. Leonard Jr. raised rents over a period of several months, with the increases ranging from 15 to 70 percent, according to David Waterman, former president of the Farnsboro Tenants Association. Elderly residents received some of the steepest increases, Waterman said.

The current rents range from $128 for a bachelor apartment without cooking facilities to $302 for a two-bedroom unit, according to Sidney Williston, a tenant.

In September, the rental commission ordered the rents lowered to their 1973 level. In November, however, the commission reversed its decision because landlord Leonard was hospitalized during the hearing on the tenants' request and was not represented. The rents went back to the pre-September level.

The tenants returned to the rental commission in December, asking again for a rent rollback. Early last month Leonard was ordered to "make a refund which reflects the adjustment in the rental ceiling as permitted by Section 206 of the Act, in the amount of $3,100." The sum is to be divided among all the tenants of the building, and the decision allows the rents to stand at the higher, pre-September level.

The rent administrator's decision said: "The tenant testimony, which was not directly contradicted by the respondent, reflects the following: 1) that no hot water service was provided from Jan. 4, 1977 to Feb. 1, 1977; 2) that no heat was provided from Jan. 4, 1977 to Jan. 7, 1977; 3) that no gas for the cooking stoves was provided for the entire month of September 1977; and 4) that from March 2, 1977 to present the subject accommodations has not been in substantial compliance with the D.C. Housing regulations." The hearing examiner concluded that services of heat, hot water and cooking gas were "substantially decreased" and "the respondent (Leonard) has demonstrated an unwillingness to deal with the tenants in good faith."

Leonard failed to return numerous telephone calls and could not be reached for comment.

Kennard said tenants received new notices at the end of March, saying that rents would be increased 7 percent effective May 1. He said that figures accompanying the notice showed, however, that in the case of 28 of the apartments, "the increases are larger, ranging up to 26 percent. The overall average increase is approximately 10.25 percent."

Waterman said that in October, while the rents were rolled back, Leonard filed an application for a certificate of eligibility to convert the Farnsboro to condominiums under the provision that the building had a "high-rent structure." Before an owner can convert a building to condominiums, he must get the eligibility certificate from the Department of Housing and Community Development. The department uses a complex formula to evaluate the rental structure of buildings and determine when they qualify for conversion to condominiums.

Abe Greenstein of the housing department said the agency is "revoking the certificate" for eligibility to convert because "at the time the application was filed the rents had been ordered rolled back" and the building did not qualify as a high-rent one. Greenstein said Leonard can apply again for permission to convert.