Patio heaters provide a comfortable environment during the cool fall and winter months by raising the nearby air temperature. These heaters typically run on propane or natural gas, and the construction is similar to that of a gas grill. Over the warm season when the heater is not in use, spiders and bugs can clog the gas tubes with webs and debris. This debris blocks the gas from reaching the igniter and requires removal for proper heater function.
Disconnect the gas line from the heater by unscrewing the coupler attached to the gas inlet valve near the bottom of the burner or base of the unit.
Remove the top cover from the heater, following the manufacturer's instructions. Typically the cover is held on by a screw and nut at the top or multiple screws around the perimeter. You may need a screwdriver to remove the screws.
Look at the burner assembly, which is where the flames typically emerge. Open a bottle of rubbing alcohol and saturate the end of a cotton swab with it. Rub the cotton swab over the holes around the perimeter of the burner assembly to clean away grease, dirt and debris that may be clogging it.
Look at the back of the burner assembly to find the venturi tubes, which are small silver tubes with holes in the end. Insert a pipe cleaner gently into the end of each tube and push it in until you feel resistance. Twist the pipe cleaner in a circle and pull it straight out to remove any spider webs that are blocking the inside.
Reassemble the cover on the patio heater by reversing the steps taken to remove it. Reconnect the gas coupler to the inlet valve and turn on the heater to test the pilot light.