Propane barbecue grills use a regulator between the propane tank and the grill. The regulator supplies propane at a constant rate through the hose to the grill. A diaphragm inside the regulator adjusts the flow by moving up and down to sense changes in the amount of gas and pressure from the tank. Regulators can pressure-lock and not let propane flow through them. You can reset a regulator so it will operate properly.
Turn off the gas valve at the propane tank.
Inspect the regulator vent that faces down. Look for any debris or insects on the screen. Brush the vent off with a toothbrush to remove any items covering it. A regulator will pressure-lock and cease to function if the air vent is blocked.
Unscrew the hose from the propane tank in a counterclockwise direction. Pull the hose off the propane tank.
Open the grill lid. Turn all of the burner knobs to the "High" position. Leave the knobs on for about two minutes. This action allows any trapped propane in the hose and grill burners to escape the system.
Turn all of the burner knobs to the "Off" position. Reconnect the gas line to the propane tank and tighten it fully. Turn the knob on top of the propane tank on very slowly.
Press and hold the electronic ignition switch on the barbecue grill. Slowly turn one burner on. As soon as the grill lights and you see flames, release the electronic ignition switch.