The regulator that connects a propane torch to the liquid propane fuel cylinder controls the pressure of the gas flow to the torch tip. This safety feature prevents the torch from raging out of control, and the regulator will shut down the torch if the gas pressure suddenly surges. The pressure of propane gas varies with a number of factors, including the amount of gas in the tank and the exterior temperature. If the regulator will not work, try troubleshooting the component before buying a replacement.
Shut off the gas flow by turning the knob on the side of the torch regulator clockwise.
Unscrew the propane canister from the regulator, leaving the regulator attached to the torch. Check the weight of the canister to be sure you are not simply out of propane. Compare the canister to another of the same size that you know is full.
Turn the knob on the regulator counterclockwise to open and bleed out the system. Any air trapped in the regulator will flow out through the torch. If the regulator feels unusually cold or is frosted, let the component come to room temperature.
Poke the end of a safety pin into the small hole on the side of the regulator below the torch nozzle. Work the pin around in a circle and side to side to dislodge any dirt or other material that might be clogging the system.
Blow compressed air into the regulator hole.
Reconnect the propane canister and try igniting the torch in the normal manner. If the regulator still will not operate, you may have a broken or malfunctioning internal valve stuck in the closed position. Do not attempt to disassemble a bad regulator. Replace the part instead.