Sales and settlements have been halted at the 310-united Regency Club of McLean condominum while the developers negotiate with their lender on the high-rise project, Manufacturers Hanover Trust Co. of New York.

Negotiations sbetween developer and principal lender apparently hinge on interpretations and renegotiations of prior agreements, extension of construction loans and even the possibility of a takeover or "buy-out" by the lender.

One occupant of the building said that some services had been curtailed but a spokesman for the developer, JVT Development Associates, said that "the continuity of the project" is a major goal.

Although no one representing the developer would say it, indications are that the developer has found it difficult to keep current with financing and other obligations because of the long and costly construction and selling period.

The spokesman said 40 apartment owners and 28 buyers who have not yet gone to settlement have been told therere is a "serious problem." Virginia law requires certain disclosure of information in regard to condominium developments because they are public offerings.

John Forstmann and Vankirk Fehr, principals in JVF Devellopment who began the project three years ago, were unavailable for comment.

The building began operating formally y y as a condominium project this spring, with the developers keeping up maintenance payments on behalf of for unsold units. The developers are also responssible for the project's $2 million tenniins club.

Generally, the problem at Regency Club is money. More than two years ago, Manufacturers Hanover Trust committed $23 million in construction funds for the first phase of a two-building development on 18 acres at 1800 Old Meadow Road, near the intersection of the Beltway and Route 123.

Built by Donohoe Construction and designed by Abel and Weinstein, prices in the 16-story Regency Club range from $44,000 for a one-bedroom unit to more than $200,000 for penthouses.