Eighteen buildings in the Yard, including all but one Yard dormitory, will lose their hot water for three hours Thursday morning and all day March 30 and 31 due to maintenance work, a Buildings and Grounds official said yesterday.

Daniel L. Campbell, mechanical foreman in Building and Grounds, said B&G plans to install larger control valves in the Yard heating system so it can produce "more steam for the greater number of people" in the Yard.

Canaday Hall, the newest building in the Yard, will not have its hot water shut off this week or during the two-day spring vacation cut off.

The other buildings that will have their hot water turned off are Widener Library, Memorial Church, and Boylston, Sever, Emerson and Robinson Halls.

Thomas F. Tierney, assistant superintendent of Facilities in B&G, said yesterday similar work is done every two years.