LYNN – City employees will not be making up work hours missed when Mayor Judith Flanagan Kennedy ordered City Hall closed by 1 p.m. Tuesday due to National Weather Service heat warnings for Lynn and other cities in Essex County.City Hall operated on its regular schedule Wednesday. Executive Assistant Mary Chalmers said the mayor cannot force employees to make up missed hours.”At this time, because of the union book, she will not be making up the hours,” Chalmers said. “There is nothing that says she has to, but she will look into changing the rules in the future.”Tuesday is typically a 12-hour city work day with offices open into the evening hours and city boards as well as the city council in session. By contrast, Friday is a short day with the hall closed in the afternoon.Oppressive mid-summer heat is an annual source of griping and occasional early closings for city workers. City Hall is cooled by portable fans with the exception of the air conditioned mayor’s office and computer equipment room. Efforts to outfit City Hall with central air conditioning present significant cost and structural problems.Kennedy said outfitting approximately 30 city offices in City Hall with portable air conditioners is an expense that could exceed $200,000.