The Friday night blaze that displaced 14 residents was caused by items left too close to a condo unit’s electric heat register, fire Chief William Laliberty said Tuesday.

The single-alarm fire at the brick Merrimack Place apartment building behind the A-1 Deli was reported by phone around 6:30 p.m. and firefighters had the blaze under control within a half-hour. All residents were evacuated and no injuries were reported.

According to Laliberty, the building’s sprinkler system activated and contained the fire to the bedroom. While smoke from the fire made its way to the adjacent Landmark Building, firefighters were able to quickly remove the smoke using fans, the chief said.