City officials estimate the air-conditioning system at the Fasi Municipal Building will be fixed no earlier than Tuesday, leaving hundreds of city employees and the site’s visitors dealing with the summer heat.

Damage to two giant chillers tied to the air-conditioning system was likely caused by the inclement weather brought by Tropical Storm Darby last weekend, city Facility Maintenance Director Ross Sasamura said Wednesday.

The regular chiller used to cool the 15-floor building, which houses a majority of city employees, failed to start Monday, as did the backup chiller, Sasamura said.

“The determination was made that both chillers were unable to start because of some damage to the compressor drive motors,” he said.

The damage was likely caused by “excessive moisture” sometime between late Friday and early Monday, he said. “We suspect it was because of the heavy rains that we encountered through Darby.”

The situation does not affect the building’s first-floor customer service center or the basement operations of the Department of Emergency Management. Both are routinely cooled by an auxiliary chiller when the main chillers are shut off after business hours, Sasamura said.

The above-ground floors of the building house the main offices for the city departments of Planning and Permitting, Transportation Services, Information Technology and Human Resources. Other major agencies also have a presence.

City Managing Director Roy Amemiya gave agency chiefs the authority to grant paid administrative leave to their employees affected by the shutdown, at their discretion, on Monday and part of Tuesday. But on Tuesday afternoon, Amemiya issued a memo rescinding that directive.

Amemiya directed agency chiefs to allow employees to work in other areas with air conditioning and allow them to “dress more comfortably to deal with the heat.”

On Wednesday, another directive asked agency heads to, among other things, allow more breaks to hydrate, provide water where fountains are unavailable, purchase fans and let employees work from home in cases where it makes sense.

The Department of Information Technology set up 30 laptops in the basement and 24 workstations at city office space in another building nearby, city spokesman Jesse Broder Van Dyke said.