SCHENECTADY — The central branch of the Schenectady County Public Library system will begin to get new heating and cooling systems starting the week of Sept. 15, Library Director Andy Kulmatiski said.

During the work, scheduled to be completed in December, the central library will be closed a maximum of four days. Tentative closure dates are scheduled for the end of October and the beginning of November, Kulmatiski said. Except for these days, the library will remain accessible to patrons during most the work, he said.

“We are looking at minimal disruption because all the work is in the basement,” Kulmatiski said. The announcement reflects changes driven by public anger at an earlier proposal that could have closed the library for a year.

The project’s budget is $86,000 for new boilers and chillers, $372,000 for mechanical work and $124,000 for electrical work.

The new equipment replaces mechanical systems original to the building, built some 40 years ago. The Clinton Street building has two boilers, but only one works, Kulmatiski said. “We want to get it out and put in three boilers before winter,” he said.

The library is using state grants to pay for most of the work.

Kulmatiski said the rehab work addresses only the building’s physical plant and not its need for additional space. Library officials want to expand the central library because of dramatic growth in circulation, which topped more than 1 million items in 2007, and to accommodate additional programming for children and adults.

The building has not been changed since its construction.

Hoping to address current and future growth, the library’s board of trustees in 2003 established a committee to design an expansion. They wanted to add a new structure between the central library and Police Headquarters, saying it would cost about $5 million.

In 2004, trustees went to the Schenectady County Legislature with the proposal for funding. The Legislature owns the building and provides more than $5 million in annual subsidies to the 10-branch system. Trustees serve in an advisory capacity.

The Legislature dismissed the trustee design committee in 2004, rejected its plan and hired a new architect for some $500,000 to develop a different design.

The architect came up with a proposal to expand the central branch itself by 9,000 square feet and replace the mechanical systems. The cost topped more than $7 million.

The Legislature’s plan called for the demolition of the distinct McChesney Room and the construction of a new entrance facing the intersection of Clinton and Liberty streets.

Architects showed their proposal to the public, but attendance at meetings was sparse.

Earlier this summer, just before the work was set to begin, a project manager hired by the county determined the central library would have to be closed for months, perhaps a year, for the work.

The news caused a public uproar and county officials quickly backpedaled. Legislators said they would seek alternative bids for the project with the goal of minimizing any closures. They later withdrew the option, instead agreeing with trustees to postpone any expansion plan and to proceed with just the repair work.

Trustees then formed another design committee, which is still working on a concept. They also established an ad hoc committee to explore creating a library district with taxing authority. The district would make the library system independent of county control. Such a district would be years from creation, however.