Bainbridge Island Fire Department Assistant Chief Luke Carpenter said the small fire at the Bainbridge Aquatics Center Monday night started after a propane-fired pool heater malfunctioned.

Carpenter, who is also fire marshal for Bainbridge Island, said a power surge was to blame for the malfunction. The heater caught fire and also ignited some of the PVC pipe that was attached to the heater.

The heater was self-contained in a small room adjacent to the Ray Williamson Pool, and the sprinkler system was activated by the rising temperature in the room, Carpenter said.

When the sprinkler system started, it also set off an alarm, and the fire department was dispatched to the scene at 8:54 p.m.

The sprinkler system put out the fire.

Carpenter said firefighters replaced the activated sprinkler head and the system was placed back in service about 10:30 p.m. Monday.