Lift the edges of the rip using a utility knife.
Slip your fingers beneath the carpet on both sides of the rip, removing the old adhesive carpet tape.
Cut a new piece of adhesive carpet tape that is equal in length to the tear in the carpet.
Push the tape into the tear, using your fingers to carefully slip the tape under both sides of the tear where the old tape used to be. Press both sides of the rip into the adhesive tape.
Allow the seam iron to heat. Once hot, slip the seam iron into the tear and allow it to heat the section of tape closest to one end of the tear for about 30 seconds.
Move the iron to the next section of tape, above the first section you ironed. Allow this section to heat for about 30 seconds. Continue moving the iron up to a new section of tape until the entire rip has been ironed.
Press the edges of the rip down firmly to ensure they attach fully to the new tape. Be careful, as the carpet and tape may still be hot from the iron.