After going door-to-door in the fall to repair furnaces, boilers and hot water heaters damaged by the Sept. 13 natural gas explosions and fires in the Merrimack Valley, Columbia Gas is setting out on phase two — replacing all the heating equipment it repaired as part of last year's "rapid relighting" process.

Officials from Columbia Gas of Massachusetts detailed plans for the company's "Spring Heating Equipment Replacement Program" at community meetings in Lawrence, Andover and North Andover this past weekend. The company said residents who had heating equipment repaired will get a call "in the coming weeks" to schedule an in-home site evaluation, which will lead to appliance replacement.

"The heating equipment replacement program is part of our commitment to supporting our affected customers in the Greater Lawrence Area and restoring these communities," Mark Kempic, chief operating officer of Columbia Gas of Massachusetts, said. "The pre-scheduled appointments and being able to provide a clear scope of work from the site evaluation will streamline the process from start to finish for our customers."

The initial evaluation will include an industrial hygienist and a mechanical engineer so the utility company "can help customers select an appropriate heating solution, including energy efficient options, and provide a clear scope of work and estimated timeline for the equipment replacement," Columbia Gas said.

After the installation, Columbia Gas will "conduct a quality assurance evaluation of the new heating equipment and an inspector will examine and approve the heating equipment installation."

Columbia Gas said the replacement program is expected to complete its work by Sept. 15 — two days after what will be the one year anniversary of the fatal gas incident.

The overpressurization event damaged 131 structures, including five homes that were completely destroyed, the National Transportation Safety Board said. One man was killed and at least 21 other people were hospitalized as a result, the agency said.