What it looks like
Low flame shows up a few ways. All burners small and blue, with the grill slow to preheat and unable to sear. Flames that start normal and fade after a few minutes. Flames that look fine with one burner on but sag when you turn on the rest. Or one burner weak while the others are fine, which is a different problem covered on our uneven heat page.
Whether the whole grill is weak, or just part of it, is the first thing to figure out. Whole-grill weakness is almost always a supply problem. One weak burner is almost always a problem at that burner.
Causes, most common first
Propane regulator in bypass
Modern propane regulators have an excess flow device. If the tank is opened quickly or with a burner already on, it trips and limits gas to a trickle. Flames stay small no matter what.
Learn moreNearly empty or cold tank
A tank near empty, or a tank in cold weather, can't vaporize propane fast enough to keep up with a big grill on high.
Spiders and debris
Blockages in venturi tubes cut both gas and air. If several burners are affected, the grill feels weak overall.
Learn moreFailing regulator
Regulators wear out, especially ones left exposed to sun and weather. Output drops and flame gets weak and unsteady.
Undersized natural gas line
A natural gas grill on a long run of small pipe, or sharing a line with a fire pit or heater, can starve when everything runs at once.
Learn moreWrong orifices
A grill set up for natural gas running on propane, or the reverse, without proper conversion. Flames will be wrong in one direction or the other.
Reset a propane regulator
This fixes a large share of weak-flame calls on propane grills.
- 1
Turn everything off
Every burner knob off, including side burners and the rotisserie burner. Close the tank valve.
- 2
Disconnect
Unscrew the regulator from the tank and leave it off for about a minute so pressure equalizes.
- 3
Reconnect and open slowly
Thread it back on hand tight. Open the tank valve slowly, a quarter turn, wait a few seconds, then open it fully.
- 4
Light one burner
Turn one burner to high and light it. Wait a moment, then light the others one at a time.
Other things you can check
- Weigh or lift the tank. A standard 20-pound tank that feels light is probably near empty.
- Check the hose for kinks, flat spots or cracks, especially where it passes under the cart.
- On natural gas, make sure the shutoff valve handle is fully in line with the pipe.
- Note whether the flame gets weaker when other gas appliances on the same line are running.
- Look at the burner flames: small and blue is a supply problem, lazy and yellow points to blocked air.
How we fix it
- 1
Measure pressure
We check gas pressure at the grill with burners running. That tells us right away whether the supply or the grill is the problem.
- 2
Replace the regulator or hose
A worn propane regulator gets replaced with the right one for the grill. Natural gas grills have their own regulator, which we check and replace if needed.
- 3
Clear the burners
Burners come out, venturis get cleared, orifices get checked and cleaned.
- 4
Check the gas line
On natural gas, if the line is undersized for the load we'll tell you what we found so a plumber can correct it.
- 5
Confirm full heat
We preheat with the hood closed and confirm the grill reaches normal searing temperature.
Weak flame questions
Why does my regulator keep going into bypass?
Usually because the tank is being opened with a knob on, or opened too fast. If it trips even when you open it slowly with everything off, the regulator or hose may be failing, or there may be a leak.
My grill gets weaker the longer I cook. Why?
On propane, a nearly empty tank or a cold tank can't keep up. Frost on the outside of the tank is a sign of that.
Can I convert my grill to get more heat?
No. Converting between propane and natural gas changes the fuel, not the heat output. Done right, a converted grill should perform like it did before.
Is the thermometer on my hood accurate?
Not always. Hood gauges can read well off. If food cooks normally and the gauge reads low, the gauge may be the problem.
How much does it cost to fix weak heat?
It depends on the cause and the parts. Call or text us with your grill's brand and whether it's propane or natural gas and we'll quote it.
Related guides
BBQ Grill Repair
On-site repair for gas grills: ignition, burners, valves, regulators, gas leaks and the hardware that wears out, with common parts carried on the truck.
TroubleshootingWhy Your Grill Won't Get Hot
The common reasons a gas grill runs cold, in the order techs check them, including the regulator reset that fixes many propane grills.
Buying advicePropane vs. Natural Gas Grills
How propane and natural gas grills differ in heat, convenience, setup and safety, and when converting a grill from one to the other makes sense.
TroubleshootingSpiders in Burner Tubes
Spider webs in burner venturi tubes are a common cause of weak flames and flashback fires. Here's how to spot it, clean it and prevent it.
SafetyHow to Do a Gas Leak Soap Test
How to check a propane or natural gas grill for leaks with soapy water, step by step, and what to do if you find bubbles.
Grill won't get hot?
Try the regulator reset first. If that doesn't do it, call or text us and we'll find out where the gas is going.