Replace a gas dryer venting hose that is inside a wall by removing the beauty ring, cutting through any caulk and installation, pulling out the vent hood, sliding in a new dryer vent and attaching the vent hood. Finish by adding spray foam insulation and caulking the area.
Unplug the dryer from the wall, and unscrew the vent hose clamp and beauty ring. Keep the materials close as you need them with the new dryer vent. After removing the beauty ring, go to the exterior wall where the vent it located, and peel away the caulk in order to remove the vent hood. Unscrew the vent hood, and set it aside for later use. Cut through any installation between the vent and the wall so that you can slide out the old vent. Clean away any of the old insulation before replacing the vent hose.
Get the new vent hose, and slide it into the hole from the exterior wall. Slip on the vent hood, and reattach it with screws to the wall. Caulk the area around the vent hood. Spray foam installation into the area between the new vent and wall from the inside of the house. Replace the beauty ring and the vent hose clamp, screwing them into place.