DULUTH — Eastern Duluth residents were asked to keep their heat down to 62 degrees through the weekend following a gas line break, when outdoor temperatures hovered near zero degrees.

A contractor on Thursday in western Duluth's Lincoln Park neighborhood drove a piling through a 12-inch gas main, one of three main feeds that supplies the city, and in this case, the eastern side of town, said Greg Guerrero, interim director of city Public Works and Utilities.

"We're hoping conservation will mean not shutting anyone off," he said.

The city worked through the night to maintain pressure, and first asked two eastern Duluth neighborhoods to lower their thermostats Friday morning. By afternoon, the city expanded its request to businesses and homes east of downtown's Lake Avenue, extending to McQuade Harbor in Knife River. The area includes about 30% of the city's natural gas customers, or about 8,000 homes and businesses.

Mayor Emily Larson said Friday the need to keep temperatures reduced could extend into Saturday, and by Saturday morning residents were asked to do so through the weekend. Midday Sunday, the city allowed the residents east of Lake Avenue to return to their normal thermostat levels.

Lowering the thermostat during cold weather isn't "easy or convenient," she said, but "your help will literally ensure residents across the city continue to get heat."

The pipe will be repaired with a temporary sleeve and a permanent fix will be made in warmer weather. A high water table in the area of the break has made work difficult, city officials said.

Larson said the leak was significant but not "particularly dangerous."

"We're being careful and cautious," she added.

Staff writer Christina St. Louis contributed to this report.