How to Cap a Gas Pipe for an Oven

Natural or liquefied petroleum gas in houses runs through black iron pipes to gas water heaters, dryers and ovens.
Changing to an electric stove requires capping the gas pipe.Changing to an electric stove requires capping the gas pipe.
When a pipe for a gas oven is no longer needed, a cap placed over the end of the pipe prevents the valve from opening accidentally, which could allow the explosive gas to escape into the home. Installing a cap on the gas pipe is fairly easy with a few hand tools and supplies and a few safety precautions.

Step 1

Turn off the gas to the home at the main valve located on the gas meter, using the adjustable wrench. The valve looks like a plug, with a rectangular end just before the pipe enters the home. Turn the valve 90 degrees to shut off the gas. A hole on the rectangular end will align with a hole on the meter to allow the gas company to lock the valve in the off position.

Step 2

Coat the threads on one end of the 3-inch black iron pipe with pipe joint compound using the brush supplied with the compound. Coat all sides of the threads.

Step 3

Screw the pipe into the gas valve behind the oven until it's hand tight. Tighten the nipple with one pipe wrench on the valve -- placed for counterclockwise turning -- and another on the pipe to turn it clockwise. The open end of the wrench's jaws face the direction you wish to turn it. Tighten the pipe one to two full turns, but no more.

Step 4

Apply pipe joint compound to the threads on the remaining end of the black iron pipe. Thoroughly coat all the threads on the pipe with compound, all the way around.

Step 5

Screw the black iron pipe cap onto the end of the pipe by turning it clockwise. Turn the pipe cap until it's hand tight. Place one pipe wrench on the cap to turn it clockwise, and the second pipe wrench on the black iron pipe to turn it counterclockwise. Tighten the cap at least one full turn, but no more than two full turns, with the pipe wrenches.

Step 6

Place 1/4 cup of water and 1/4 quarter cup of dish soap into the spray bottle. Mix the solution with the plastic tube on the spray bottle cap. Screw the cap on.

Step 7

Turn the gas valve on the meter to the on position by rotating it 90 degrees with the adjustable wrench. Examine the pipe cap inside the house. You should not hear any hissing that indicates gas is escaping.

Step 8

Spray the all the pipe threads with the soap solution. Observe the connections for two minutes. Foamy bubbles that form and grow indicate a small leak. If necessary, tighten the cap in small increments to stop leaking gas. Retest for leaks each time the cap is turned.

Things You Will Need

  • Adjustable wrench
  • 3-inch long black iron pipe
  • 2 pipe wrenches
  • Pipe joint compound for gas
  • Black iron pipe cap
  • Dish soap
  • Spray bottle


  • Teflon tape for gas is yellow and approved for use on gas pipes. Don't use the white Teflon tape which is not approved for gas. To use Teflon tape, wrap the tape clockwise along the full length of the threads to cover them with three to five layers of tape.


  • Don't allow the pipe to turn when you remove the valve. If the pipe turns, you must remove the pipe, put new compound on the threads and reinstall it. Prevent the pipe from turning and test the connection between the pipe and the fitting for leaks if it turns.
  • Even though the end of the pipe has a valve on it, turn the gas off to prevent accidental gas discharge.

About the Author

Michael Logan is a writer, editor and web page designer. His professional background includes electrical, computer and test engineering, real estate investment, network engineering and management, programming and remodeling company owner. Logan has been writing professionally since he was first published in "Test & Measurement World" in 1989.