Firefighters say it took three hours to put out a blaze at South Horizons in Ap Lei Chau early yesterday because the building's fire hydrant system did not work. Water had to be pumped all the way up from the ground to Flat B on the 17th floor, where an air conditioner was believed to have caught fire. Seven people were injured, including a 21-year-old man who lived in the flat, a fireman and a one-month-old boy. A nine-year-old girl and her mother, 32, were in serious condition with burns at Queen Mary Hospital in Pok Fu Lam last night after being rescued from the 21st floor stairwell. More than 200 residents of block 10, known as Yee Lai Court, were evacuated when the blaze broke out at 6.12am. Many of them complained the fire alarm was not loud enough and that firefighters took a long time to reach them. With no direct road access to the burning flat, fire engines were seen going through a car park and stopping nearby at the waterfront. One man, who lives on the 23rd floor, said he was aware of the fire only when his neighbours knocked on the door. "We were very lucky that this wasn't a lot more serious because most people didn't even know there was a fire," he said. Ann Li, 26, who is pregnant and lives on a lower floor, said she saw an occupant of Flat B run half-naked from his home. She heard the man say he had been using the air conditioner all night to dehumidify his flat and that it had exploded suddenly. Sanjay Jayaram, 62, who lived opposite Flat B, said the smoke was thick and he could barely breathe. He said the flat's occupant knocked on every door on the 17th floor to alert neighbours. Nitin Advani, 46, said the fire engine ladders were not long enough to reach the blaze. Leung Chi-hung, deputy chief fire officer for Hong Kong Island, refuted the criticism. Firefighters were on the scene in four minutes, he said, but the building's fire hydrant system was faulty. "The hydrants had water, but there wasn't enough pressure to douse the fire. So the firefighters had to use our own hose and pump water from the ground to the fire," he said. The hydrants had water, but there wasn't enough pressure to douse the fire. So the firefighters had to use our own hose and pump water from the ground to the fire Leung added that fire engine ladders were used only to control the blaze from spreading. It was mainly put out from inside, not outside, the building, he said. The contractor responsible for the fire hydrants said the system short-circuited during the incident. But former fire chief Lam Chun-man said he had never heard of short-circuiting in such a system, which usually had reserve battery power. Andrew Fung Wai-kwong, district councillor for South Horizons West, called for a thorough check of all fire systems in the 34 blocks of the private estate. He said a path should be created for emergency access. [Above video taken by South Horizons resident.]