The Fire Department, which was so understaffed last year that a fire truck was occasionally taken out of service, has hired five firefighters. Acting Chief William Spillane introduced the recruits during a meeting of selectmen, who expressed relief that the problem was resolved. The five are Matt Kanelos, Ryan Scaccia, Eric Levesque, Eddie Jones, and David Sheehan. Late last year, facing a potential of $1 million in firefighter overtime pay, town administrators took a fire truck out of commission on days the department was understaffed, a move Dedham’s firefighters’ union protested. The truck was put back in service while new hires were sought.