A broken mobile boiler has left 2,440 tenants in a Bronx public housing complex without heat on a day when wind chill temperatures dipped into the 20s.

Wednesday marked the coldest day of the season, resulting from an arctic blast moving across the eastern United States.

A spokesperson for New York City Housing Authority confirmed that a heat and hot water outage at NYCHA's Pelham Parkway development in the central Bronx occurred at 5 a.m. NYCHA heat crew and electricians were said to be on site in hopes of restoring heat by the afternoon.

NYCHA has in recent years experienced chronic and widespread boiler problems that have left many of its 400,000 low-income tenants in the cold. Last winter, more than 150,000 of the total 174,000 units—or 87 percent—lost heat or hot water at some point. According to a recent New York Times story, boiler systems at many public housing buildings are on the edge of breaking down. More than half of the 1,713 boilers are more than 20 years old, which is when they typically need to be replaced.

Facing $32 billion in capital repairs, the housing agency has struggled to maintain and upgrade boiler systems. As part of NYCHA's federal monitor's preliminary approval for $450 million in state spending, $363 million was allocated for upgrading outdated boilers. But the process of installing new boilers could still take years. The authority has said that it can take three to four years to design, fabricate and install a boiler.

Last year, Mayor Bill de Blasio announced a plan to spend $82 million to install 39 replacement boilers by 2022.

By law, during the heat season, landlords must maintain inside temperatures of at least 68 degrees if the daytime temperature outside falls below 55 degrees. At night, apartments must be at least 62 degrees.

In anticipation of the freezing weather, NYCHA on Tuesday postponed planned outages at several complexes across the city.

UPDATE: An earlier version of this story incorrectly referenced 150,000 tenants who went without heat at some point last winter. It was 150,000 units.