On a propane grill, a device known as propane regulator attached to the propane tank shutoff valve controls the flow of gas to the burners. Its purpose is to ensure that the flow is maintained at a uniform rate. Sometimes, though, an internal part on the regulator, known as the bypass valve, may become stuck. When this happens, you may notice that the gas sputters or fails to reach the grill burners. Or, if the grill fails to heat above about 250 or 300°F., it may be that the regulator is failing to deliver the full amount of gas.
Usually, this happens because the bypass is partially or fully stuck in the closed position inside the regulator. The solution is pretty simple: disconnect the regulator from the tank to release any internal pressure. This usually resets the regulator back to proper operating condition.
Here's how to reset the propane regulator on your grill.
Open the cover lid on your gas barbecue and turn all burner dials to the OFF position. Turn the shutoff valve on the propane tank to the OFF position by turning rotating the valve in clockwise direction until it is fully closed.
Disconnect the regulator from the propane tank shutoff valve by twisting the knurled mounting knob in a counterclockwise direction. The regulator should now simply pull away from the propane tank valve.
Open the burner control knobs on the grill fully. This will release any pressure in the gas lines. Wait 30 seconds for the regulator to reset itself.
Reattach the regulator to the propane tank shutoff valve by threading the mounting knob back onto the valve. Screw the mounting knob in the clockwise direction until it is tight.
Open the propane shutoff valve slowly by turning the valve handle in a counterclockwise rotation. Test the grill by opening the burner valves and using grill's controls to ignite the burners. If the grill still refuses to operate correctly, the regulator may need to be replaced.