Long-awaited work to restore permanently cooled air to Metro's Dupont Circle and Farragut North stations will require months of closures of Connecticut Avenue in Northwest.

WASHINGTON — Long-awaited work to restore permanently cooled air to Metro’s Dupont Circle and Farragut North stations will require months of partial lane closures along Connecticut Avenue in Northwest.

The dig work needed to replace leaking pipes will affect sections of both the northbound and southbound lanes of Connecticut Avenue and is expected to run from Nov. 5 through late March, Metro said Friday.

Metro used a temporary cooling tower placed next to the sidewalk this summer and part of last summer to bypass the deteriorated pipes.

For the first two weeks, until just before Thanksgiving, crews are scheduled to close parts of Connecticut Avenue between Desales and L streets Northwest, north of Farragut Square, only during the middle of the day — from 9:30 a.m. to 3:30 p.m.

After that preparation work is done, the construction will block parts of northbound and southbound lanes of Connecticut Avenue around the clock for excavation.

Later, work will be done overnight only as new pipes are installed beneath the road.

As part of the work, a crane is scheduled to lift pipes Nov. 10 to the permanent rooftop cooling tower on the roof of an office building above the Farragut North station. That work will block part of L Street that Saturday.

Metro aims to have the cooling system up and running in time to turn it on as normally scheduled in May.

The system has been failing for years.