On Saturday January 6, 2017 at 0657 hours, Battalion 2 was dispatched to the Compass Self Storage Facility for a fire alarm activation. Crews from Engines 921 and 922 arrived and investigated finding a smoke condition in the storage area at the C/D corner of the building. 9201 upgraded the assignment to the building, bringing resources from Battalion 3. Crews continued to investigate and narrowed the source of the smoke to a wall mounted heater in the area. The heater was shut down and power secured and the crews ventilated the smoke. The building was turned over to a representative and crews Available.