Palo Alto's frustrating slog to rebuild the Mitchell Park Library and Community Center is facing a fresh wave of construction setbacks, pushing the estimated completion date of the beleaguered project to early spring of 2014.

The new problems, including faulty alarm systems, water leaks and broken pavers, represent the latest obstacle for the city's largest capital project, the cornerstone of the $76 million bond voters approved for library renovations in November 2008. Since construction began in 2010, the project has fallen behind schedule thanks to deficient work, failed inspections and bitter disputes between the city and its contractors.

According to a letter that Public Works Director Michael Sartor had sent to Tom Maxwell, president of the construction company Flintco Pacific, the project continues to face unexpected complications, mostly resulting from Flintco's defective work. The letter, which the City Council discussed and approved in a closed session Tuesday and which the city publicly released Wednesday morning, spells out more than a dozen problems at the city's most notorious construction site near the intersection of Middlefield Road and East Meadow Drive. These include roof leaks that have not been repaired, fans that haven't been properly installed and, most alarmingly, a fire-alarm system that has failed three tests. In an interview Wednesday, Sartor described the lattermost problem as "very disturbing and a big deal."

His letter to Maxwell also noted that Flintco has failed to install several required fire-extinguisher cabinets and restroom accessories.

"There is no excuse for Flintco's lack of effort to correct these problems," Sartor wrote. "Flintco's current level of effort is unacceptable."

As a result of these problems, the city no longer expects the project to open to the public by the end of the year. In his letter, Sartor wrote that he expects Flintco to correct these problems and issue a "temporary certificate of occupancy" for the library building by Nov. 27. This would allow staff to move into and start equipping the new building. Even in this best-case scenario, the process for getting the library ready for usage would take a few months, pushing the earliest possible opening date to somewhere around February or March.

Yet the rocky saga of Mitchell Park gives few reasons for the city to expect a best-case scenario. While much progress has been made in the past few months, pushing the completion level to about 96 percent as of early October, many problems remain unsolved. According to Sartor's letter, Flintco has failed to test and balance the heating and air conditioning systems in the new building, a key step for the building to pass inspections.

To compound the issue, the problem of insufficient staffing that Flintco seemingly resolved last summer is once again plaguing the project. In June, after the city threatened default proceedings, Flintco upped its workforce and finally made progress on the library building. In recent weeks, however, the number of workers on the site dipped again despite the long list of things to do. Sartor notes that the personnel gains "now appear to have been lost" and argues that there is "no apparent reason for Flintco reducing the number of personnel working on the Project."

Sartor's letter notes that the average subcontractor labor has dropped to about 15 to 16 workers per day, while Flintco's average manpower is four to five workers, many of whom do not work for an entire shift.

"There has been little effort to address the large number of defective work issues that have been identified," Sartor wrote.

In his letter, Sartor requests a "firm commitment" from Flintco to have "temporary certificate occupancy" for the library building by Nov. 27 and for the community center by the end of the year. He said Flintco officials have assured him that they will meet these deadlines.

"If Flintco performs, then we would have temporary occupancy by the end of the year for the whole project and then we'd be able able to open the buildings to the public a few months after that, in the February, March timeframe," Sartor told the Weekly on Wednesday. "Assuming Flintco performs. That's the question."

In his letter to Flintco, Sartor wrote that "continued lack of diligence of Flintco's part is likely to result in termination of the Contract." This, however, would carry its own consequences for the city. If Palo Alto has to switch to a different contractor, the timeline for the project would be extended even further and the library likely won't open until summer 2014 at the earliest.

"If they don't perform, we're probably talking about a couple of months additionally," Sartor said.

So far, the city had spent about $28 million on the construction project, Sartor told the Weekly. It has about $1 million remaining for construction in its contingency budget. In addition, the city had begun to retain 10 percent of its payments to Flintco and now has about $2.2 million available in retention payments.

In his letter, Sartor noted that Flintco had promised to have the library ready for occupancy within a few weeks, a milestone that now seems unlikely to be reached.

"Representatives of the City have come and inspected the progress of work," Sartor wrote. "There are many areas that Flintco and its subcontractors are working on, but Flintco appears either unable or unwilling to commit an adequate amount of personnel to complete the Project any time soon."