Why Your Grill Won't Get Hot

Before anything else, light every burner on high and look. The flame tells you which direction to go.

• Small, low blue flames on all burners: not enough gas is getting through. Think regulator, tank, supply line or valves.
• Tall, floppy yellow flames: gas is flowing but not mixing with enough air. Think blocked venturi tubes or air shutters.
• Healthy flames on some burners, weak or missing on others: a burner, valve or orifice problem specific to those positions.
• Healthy flames everywhere but still not hot: heat is escaping, or the thermometer is wrong.

A natural gas grill has no tank to reset, so the usual suspects are the supply line and the grill's own valves and orifices. Natural gas is delivered at much lower pressure than propane, which means the gas line to the grill has to be sized for its distance and the grill's demand. A long run of narrow pipe or flexible line can starve a large grill, especially if a pool heater or fire pit shares the line.

If the grill used to get hot and suddenly doesn't, check that the shutoff valve is fully open and look for spiders in the venturi tubes. If it has never gotten hot since it was installed or converted, the supply line size or the conversion itself is the likely culprit. See propane vs. natural gas grills for more on how the two differ, and our conversion service if the grill was switched from propane.

A grill with perfect flames can still struggle if heat isn't contained. Heat plates (also called flavorizer bars or briquette trays) spread and hold heat; when they're rusted through, the burners heat the air and not much else. A hood that doesn't close squarely because of a worn hinge vents heat out the back. And a wind-exposed grill on a hillside deck will run cooler than the same grill in a sheltered courtyard.

Finally, check the gauge. Hood thermometers measure air near the top of the hood, which is cooler than the grate. Many are also simply inaccurate after a few years. If food is cooking at a normal pace, the grill may be fine and the gauge is the problem. A replacement gauge is a small fix.