From various fund-raisers over the last year, the 30-member Harvard Firefighters Association has raised $4,000 to help offset the $17,000 cost of thermal-imaging cameras and gear lockers that were installed last week, said Richard Sicard, chief of the all-volunteer department. “We wanted to give something back to the town,” added William Barton, treasurer of the association, noting that the next fund-raiser will be the Ken Harrod Memorial Bike Ride through town on Sept. 22. Harrod was a longtime local firefighter.