Gas springs are used to operate the main valve on Formula 1 racing cars.

When an engine is operating, the main valves are fully open.

Be sure the main valve, which turns the radiator on and off, is fully open.

They park cars perpetually over the main valve outside to keep the utility company from turning off the water each fall.

Be sure the main inlet valve is fully open.

Turn off the gas at the outside main valve if you can and call the gas company from a neighbor's home.

This may mean closing the main water-supply valve on the street side of the water meter.

He waited in the little compartment where the main valves of the ventilation system were located.

I have pressure on number two main valve.