The Planning Board at its meeting Thursday will continue a public hearing into a proposal by Lahey Hospital & Medical Center to locate a backup diesel generator at its 29 Burlington Mall Road building. Lahey seeks approval of a minor engineering change to its site plan, and also approval of a special permit it needs to store diesel fuel in a water resource district, according to Don Benjamin, the town’s senior planner. In another continued hearing, the School Department is seeking approval of its plan to make improvements to the high school parking lot, including restriping, repaving, and modifying the entry way. The board will also resume discussion of a proposed zoning change to expand the areas in town where parking garages are allowed. It will continue a hearing into a proposal by Muller Glen LLC to make minor engineering changes to its site plan for Holly Glen, a development of 32 single-family homes now under construction off Muller Road. The change would provide for the homes to be heated by propane gas instead of natural gas. The board will also resume a public hearing into a request by Verizon Wireless to place equipment on an existing 190-foot cell tower owned by American Tower at 51 North Ave. Verizon is seeking approval of minor engineering changes to the site plan to place its antennae on the tower and to install ground-level equipment.