A RESTAURANT manager who switched on an air conditioner, causing an explosion, died accidentally, a coroner ruled yesterday. The accident occurred at the Treasure Restaurant in King's Road, North Point, on April 28 when maintenance work was being carried out on the air conditioner. Kong Lin-ching, the assistant manager of the restaurant, was seriously injured in the explosion. He died of broncho-pneumonia and intracerebral haematoma on May 20 in Queen Mary Hospital. The court was told that the explosion was caused by a buildup of pressure inside the compressor of the air conditioner when the refrigerant pipes had not been reconnected. Coroner Rodney Venning recommended that those who undertook potentially hazardous maintenance work should put up warning notices or take steps to prevent access to the work.