STAMFORD — Maintenance workers got a bit of a surprise Monday afternoon while they were replacing a water heater in the basement at 9 Woodland Avenue. Stamford Police Captain Richard Conklin said when the workers removed the old water heater, they found a .40-caliber semi-automatic pistol concealed behind the machine. “Someone had rigged a coat hanger to make a sort of hook and hang the gun behind the water heater,” Conklin said. “The gun was fully loaded, with nine bullets in the clip and one in the chamber and the weapon’s safety was off,” he said.