Firefighters were called to a blaze on a hotel's roof terrace in Stratford.
The fire at the International Way venue, which also has a restaurant, happened at around 6pm on Sunday (May 2).
No-one was injured, a London Fire Brigade (LFB) spokesperson said.
A cooking range and extractor unit in a self-contained kitchen on the roof terrace were damaged by the fire, which LFB took 12 calls to.
The blaze was brought under control just before 7.45pm.
The LFB spokesperson added: "The brigade's fire investigators believe the fire was accidental and was caused by a fault in the control unit for the extraction system."
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