Public Warned of Fire Risk From Heaters : Safety: About 1,000 residents are instructed to turn off furnaces at night as the gas company replaces a potentially defective part.

With nighttime temperatures plunging to the chilly 30s, about 1,000 gas customers in the Ojai Valley and portions of Ventura were warned Thursday to turn off their heaters at night because a potentially defective part could ignite a fire.

Workers for Southern California Gas Co. hand-delivered the notices to residents and are working overtime to replace the components, said Marcia Secord, the gas company’s district manager for Ventura County.

Only residents who received a notice Thursday need be concerned about the problem, she said.

It is the second time this year that gas company officials have sent out teams to replace potentially faulty parts. Since mid-August, the utility has replaced certain controls on furnaces in 34,000 homes in the Ojai Valley and Ventura because impure gas had degraded some parts, Secord said.

But in about 1,000 homes, the replacement parts were also potentially defective, the company learned.

Some of the recently installed control boxes may stick, causing the furnace to overheat and, possibly, explode into flames, Secord said. Gas company officials hope to have all affected parts replaced by Tuesday, she said.

The bulletins were distributed two days after a mobile home containing the faulty part burned in Meiners Oaks. No one was hurt in Tuesday’s fire, but investigators determined that it had started in the heater, Secord said. Utility officials want to make sure other potentially dangerous valves are replaced, Secord said.

Until the boxes are replaced, customers are being advised to turn their heaters off when they go to bed or if they leave home, Secord said. They also should use only the thermostat to turn off the heater and not turn off any electrical power to the furnace, she said.

During waking hours, customers who received notices should pay close attention to the operation of their heater, Secord said. If it does not shut off within five minutes after the thermostat is turned down, if it seems to be overheating or if it emits an unusual odor, customers should immediately call the gas company for service, she said.

Between 7 a.m. and 9 p.m., residents should call (800) 427-7177; after 9 p.m., call (800) 427-2200.

The gas company first learned of the problem in October, when New Jersey-based electronics manufacturer ITT said it was recalling controls made between April and October because valves were sticking, Secord said. ITT technicians were in the process of checking the controls already installed when the mobile home in Meiners Oaks caught fire, she said.

Because of the blaze, the gas company decided Wednesday to send out notices about the potential problem and speed up inspections, she said.

With blustery cold days and even chillier nights forecast for the next few days, Secord acknowledged that the furnace problem could not come at a worse time. Still, it is better to be safe, she said.

“We regret any inconvenience this may cause our customers,” she said.

To keep warm at night, Secord suggested that residents wear extra layers of clothing and throw an extra quilt on their beds. It also helps to wear a cap or some other hat to keep heat inside the body, she said.

The gas company will provide electric space heaters to affected customers concerned about keeping warm, she said.