First of all, let me say that if your grill is getting on in years, has been experiencing increasing problems for a while, or shows signs of rust, wear or age in its internal parts (burners, etc.), then it is probably in need of repair. Gas grills generally don't last forever and many lower quality models only last a few years. However, if your grill is relatively new and in good shape and suddenly starts acting up, then you can probably get it back to good working order quickly and easily.
Safety First: Always make sure that you have turned off your tank valve and disconnected your grill from its fuel source before you do any work on your grill. If you have had your grill on, make sure it has cooled down. If you had the gas on, give the grill five minutes for it to dissipate.
1. Low flame, low temperature, yellow flame: This has become the biggest problem with many grills recently and is almost always because of the regulator (the funny UFO shaped thing on the gas hose). Regulators seem to be stickier these days and when they stick you won't get enough gas to generate a good grilling temperature. To reverse this, you need to release the pressure on the regulator. Follow these steps exactly:
- Turn off the gas at the propane tank
- Disconnect the gas line from the tank
- Open the grill lid
- Turn all control valves to high
- Wait for about a minute
- Turn all control valves to off
- Reconnect the gas line to the tank
- SLOWLY turn on the gas at the tank
- Light the grill normally
- Your grill should now heat normally
To keep the regulator from sticking again, make sure to turn off the control valves first, then turn off the tank valve. Always open the tank valve slowly.
If this doesn't work give it a second try. If you still have low flame, then you probably have a faulty regulator that will need to be replaced.
2. Uneven heating/hot spots: Most grills have uneven heating. Of course, this doesn't mean that one part grows volcanically hot while other areas are cool enough to park your drink on. The number one reason for uneven heating is a blocked burner. Burners have a series of holes or ports along the sides that gas flows through to produce flame. Frequently, drippings run over the burner and causes clogging. You can use a wire brush to remove these deposits from the burner and be in good shape. Sometimes the burners become so clogged that you will have to remove the burner from the grill to clean it. Some grills you can simply lift out the burners, others are bolted in and difficult to remove. If you can easily remove the burner from the grill, clean the area thoroughly with a stiff wire brush. Make sure to get all the gunk out from the inside of the burner. Do not use oven cleaner or harsh detergents on your burners; some can be very delicate and prone to rusting.
3. It just won't light: Some grills have push button (piezo-electric) igniters and others are battery powered. If you have the battery type, try replacing the batteries (hey, it's worth a try). What you need to find out is if you are generating a spark in the igniter unit. The igniter is going to be near one (or several) of the burner(s). Some grills have independent ignition, some have a single igniter. If you have independent ignition and none of the burners will light then you have a faulty button or the wiring is bad. You might have to get these parts replaced. If you have independent ignition and one of the burners will not light, or you have a single igniter and none of them will light, you probably have something clogging that igniter. Pull off the cooking grates and barrier to get down to the burner. Locate the affected igniter and push the button. You should see a spark. If the igniter is clogged, carefully clean it out and test it again. If there is nothing clogging the igniter then you need to inspect the wiring. Faulty wiring or switches must be replaced.