LYNN – As firefighters balanced a ladder on icy ground Friday, Lt. Matthew Reddy climbed to a third-floor window of a burning triple-decker on Johnson Street and rescued a man as another crew assisted him from inside the tenant’s apartment.Edgar Fuentes, 37, was taken to Union Hospital for smoke inhalation and observation while firefighters battled a three-alarm blaze that broke out at 63 Johnson St., in the heart of the downtown on a street that runs behind City Hall, at 9:58 a.m.Fire investigator Lt. David Legere said an initial investigation indicated the building’s owner, Alexander Bogomolov, started the fire while thawing out basement pipes with a heat gun.”It couldn’t have started in a worse place: It went right up to the third floor,” Legere said.District Fire Chief Lee Oliver said the fire climbed the building, racing along pipe chases up to the third floor where it spread through the roof.”It had been burning a while before anyone noticed,” Oliver said.Engine 1 firefighters arriving on Johnson Street entered the smoke-filled building and with the aid of breathing equipment climbed to the third floor.Ladder 2 firefighters under Lt. Raymond Kane carried a portable ladder to the front left window on the top floor and raised it to rescue Fuentes, who Fire Chief Dennis Carmody said, “was hanging out the window.”The Engine 1 crew reached the top floor in time to assist Fuentes while Reddy helped him onto the ladder.”He didn’t have any problem. He was ready to go,” Oliver said.Tenant Octavio Martinez said he noticed smoke in his top-floor apartment and left the building with his wife, Florinda, and 1-year-old son, Estaban Alonzo.Neighbor Quentina Seidi, 57 Johnson St., opened her home to the Martinez family and several second-floor residents.”I saw little kids without shoes. They looked in distress,” Seidi said.Oliver said 63 Johnson is home to 10 adults and four children who were receiving Red Cross emergency housing assistance Friday afternoon.Fire scene commanders declared the fire out at 1:18 p.m.Firefighters overcame two challenges to battle the blaze, including its location and mechanical difficulties. Engine 1 burst a radiator hose and firefighters employed a backup engine and 700 feet of pump line to keep water flowing through the engine and onto the fire.The building’s location, set back from Johnson Street and slightly behind another building, constricted the firefighters’ work area.Oliver and Legere said the building’s smoke alarms were functioning. Oliver said the building is “repairable.”