Chicago Public Schools plans to at least double the number of schools where building services are privately managed this summer but won’t yet say how many Board of Education engineers will lose their jobs in the process — nor how much money the move might save the broke district.

CPS currently pays SodexoMagic to oversee engineers as well as their janitors in 33 of its schools. That $80 million three-year contract was forged at the same time as the controversial $260 million Aramark deal in the winter of 2014.

Aramark’s performance — which immediately sparked the ire of principals — overshadowed those of SodexoMagic, but the district insisted Thursday that the SodexoMagic pilot schools felt “very positive” about their services.

So on Thursday, CPS launched a request for proposals to expand the building management, starting this summer.

In a letter to engineers on Monday, CPS said it would fully move to private management by the summer of 2018. That means more than 500 engineers could lose their jobs, and if hired back, would move into a separate union for private-sector workers, according to CPS.

“CPS appreciates the dedication and hard work of its engineers, and it is important that you know that the decisions are being made and contemplated are about efficiency and not about how much your work is valued,” chief administrative officer Jose Alfonso de Hoyos-Acosta wrote. He added that CPS will require vendors to hire back engineers who get laid off in the process.

Hoyos-Acosta also told principals in a similar letter that “Our objective is to minimize staff disruption; unlike previous service delivery models, we will work to minimize any potential turnover or bumping,” adding, “I know from conversations with many of you that the way facility services have been provided to you this year has been challenging.”

The Board of Education currently employs about 520 engineers in its 600-plus buildings who are in charge of each school’s boiler, heat and other major infrastructure. Many of them are responsible for more than one building, which some say leads to problems such as a boiler leak at Prussing Elementary School last fall. About 80 children and staffers were hospitalized after carbon monoxide pervaded the building. The engineer who was assigned to Prussing part-time had had complained about the boiler’s problems.

An official at International Union of Operating Engineers Local 143, which represents the engineers, declined to comment. The local has a meeting scheduled for Thursday night.

In recent years, CPS moved engineers from under the authority of each school principal to a downtown manager, which led in some cases to headaches, principals and engineers alike have told the Chicago Sun-Times.

“Over the past two years, we have heard concerns about the way facilities services are provided in some of our school buildings,” spokesman Michael Passman wrote in a news release. “The district has worked to address individual issues but we recognize an alternative approach may be necessary to improve facility services throughout the district.”