The March 13 fire at Famous Dave’s restaurant was caused by a malfunctioning water heater, Kalispell Fire Chief Dan Diehl said Monday.

The fire that shot along the space between the ceiling and the barbecue restaurant’s membrane roof started in the mechanical room on the southwest corner of the building, ending with structural damage that Diehl estimated at $250,000 on the night of the fire.

“The reason for it to catch fire is still unknown,” he said.

Investigators with Travelers Insurance completed their investigation of the scene last week, he added, and planned to send the water heater to be analyzed.

“We will participate in the after-action with them once they’ve determined what happened with the water heater,” he said. “That’s good closure to a fire like this.”

Diehl also said smoke- and fire-detection systems in the popular barbecue restaurant on U.S. 93 were on when the fire started.

“It doesn’t appear the smoke system was shut down,” he said. “All the systems were in place at the time of the fire, from what I can determine from the fire alarm system.”

Famous Dave’s contracts with a central monitoring station in Billings that remotely tracks fire detection systems and places the 911 emergency call when needed. From his conversation with the company, Diehl said he believes the restaurant’s systems were functioning normally until the heat got more intense.

“It appeared … the alarm at some point didn’t sound, possibly due to the fact that wires in that room were melted,” he said. “They were up above the ceiling and sustained heat and smoke damage.”

He added that smoke detectors in the required locations — fire code does not require a detector in every room — and the sprinkling system were in place.

He said a monitor that tracks water flow from sprinkler heads showed that they never kicked on during the fire. Each sprinkler head is triggered individually by heat in the vicinity. The sprinkler system operates independently of the fire alarm system.

If a fire had to happen, an occupied restaurant was the best scenario, Diehl said. Firefighters were called as soon as the smoke was spotted inside and people were evacuated, rather than waiting for more damage to trigger an alarm or passers-by to see the flames.

Famous Dave’s General Manager Michael Schindler worked all last week with crews of restaurant employees to haul away spoiled food, tear out wood flooring, scrub walls and do fire cleanup under the direction of a restoration specialist.

He said on Thursday that, even though the insurance investigators were still at work, he still is gearing up to reopen by summer.

Reporter Nancy Kimball may be reached at 758-4483 or by e-mail at nkimball@dailyinterlake.com