Lewiston firefighters examine the roof of the Burger King on Lisbon Street after putting out a fire which broke out around 7 a.m. on Sunday morning.

LEWISTON — A fryolator at the Lisbon Street Burger King was blamed for a fire that closed the restaurant Sunday morning and caused heavy damage to the machinery and duct work, a fire investigator said.

Flames leapt out of the back of the fryolator from the machine beneath, Fire Inspector/Investigator Paul Ouellette said.

No customers were in the restaurant at the time, he said.

When the flames appeared, an employee initiated the fire-suppression system in the area, and its nozzles sprayed a wet chemical agent toward the open top of the fryolator. The chemical turned to foam on contact with the hot grease.

But the flames at the back of the fryolator machine continued and shot up the venting duct work to the roof, Ouellette said.

Seeing that the suppression system wasn’t aimed at the flames, several employees aimed fire extinguishers at the flames near the back wall as the restaurant filled with smoke, Ouellette said.

He said the restaurant sustained about $20,000 and was expected to be closed for one to two weeks for cleanup of the fryolator area, powder residue and smoke.

A sign is seen in the window of the Lisbon Street Burger King in Lewiston. The business was closed due a fire on Sunday morning.