Grill Won't Get Hot? Here's What to Check

You light the grill, you set everything to high, and 20 minutes later the thermometer reads 350°F. It used to hit 600°F. Something’s wrong, but it’s not on fire and the flames look… mostly normal?

This is one of the most-common grill problems and one of the easiest to fix. The cause is almost always one of five things, all diagnosable in under 15 minutes.

Cause 1: The regulator is in safety lockout (most common)

Modern propane regulators have a built-in safety mechanism that triggers when gas flow exceeds expected rates. Once tripped, the regulator restricts flow to about 30% of normal — enough to light the burners but not enough to reach high heat.

The trigger: opening the tank valve too quickly. Once tripped, the regulator stays in lockout until manually reset.

Symptoms: grill lights normally but won’t reach high heat; flames look smaller than usual; problem started after a tank swap or regulator reconnect.

Fix (5 minutes):

1. Turn all burner knobs off
2. Close the tank valve completely
3. Disconnect the regulator from the tank
4. Wait 60 seconds
5. Reconnect the regulator
6. Open the tank valve slowly — count to 10 as you open
7. Open burner knobs, light, run on high for 5 minutes

This resolves the most common cause of low heat. If the grill returns to high temps within 5 minutes, you’ve found it.

Cause 2: Spider webs in venturi tubes

Spiders nest in the air-intake openings of gas burners, especially in spring and after weeks of cooker disuse. A blocked venturi tube produces weak heat and yellow flames — the burner can’t get enough air-fuel mixture for proper combustion.

Symptoms: weak heat, yellow flames on one or more burners, problem appeared after the grill sat unused.

Fix: pull burners, inspect venturi tubes, clear with a venturi brush. Full procedure in Spider Webs in Your Grill Burner Tubes. 15 minutes.

Cause 3: Empty or near-empty propane tank

The grill needs adequate propane pressure for full heat. A tank under 1/4 full produces inconsistent pressure, especially on hot days when gas vaporization rates are at their peak.

Symptoms: heat output decreases as the cook progresses; tank feels light when lifted.

Fix: weigh the tank. Empty tanks weigh 17-18 lbs (the “tare weight” is stamped on the collar). Full tanks weigh 37-38 lbs. The difference is propane in pounds. If your tank has under 5 lbs of propane, swap it.

Cause 4: Clogged burner ports

Grease buildup, food residue, or rust can clog the small holes (ports) along the top of each burner. Clogged ports produce uneven flames and reduced total heat output.

Symptoms: visible patchy flames (some bars dark, some bright), gradual heat reduction over months, grill that needs regular cleaning hasn’t been cleaned in a while.

Fix: pull the burners, brush across the top with a stiff brass brush, clear individual stubborn ports with a paperclip. 20 minutes.

Cause 5: Burner damage

Less common but possible: burners can develop cracks, holes, or corrosion that prevents proper flame patterns. Damaged burners produce weak, inconsistent heat that no cleaning fixes.

Symptoms: visible damage to burner tubes, flame patterns that don’t match neighboring burners even after cleaning, persistent issues after addressing other causes.

Fix: replace the damaged burner. Replacement burners are model-specific, run $30-100 each, and are owner-installable in 30 minutes.

The diagnostic order

Work through these in order — the first three are free and fast, only escalate if needed:

1. Reset the regulator (5 minutes, free)
2. Check propane tank weight (2 minutes, free)
3. Inspect venturi tubes (15 minutes, free)
4. Clean burner ports (20 minutes, free with brushes you should have)
5. Replace damaged burners (30 minutes + part cost)

About 70% of “grill won’t get hot” cases resolve at step 1. Another 20% at step 2 or 3. The remaining 10% require steps 4 or 5.

Edge cases

Grill won’t get hot AND won’t light: usually an empty tank or a closed valve. Check those first.

One burner won’t get hot, others are fine: that specific burner has a clogged port, damaged tube, or local venturi blockage. Address that burner specifically.

Grill gets hot for 5 minutes then drops: regulator issue, tank pressure issue, or in rare cases a thermostat-style safety mechanism. Reset the regulator first.

Grill was fine yesterday, weak today: regulator lockout (most likely from disconnecting/reconnecting the tank since yesterday).

Grill has been weak all season: probably needs a full cleaning. Skip the diagnostic and do a full deep clean — that addresses multiple causes at once.

When to suspect something else

If you’ve worked through the diagnostic and the grill still won’t reach high heat:

• Charcoal grills: airflow issue. Check that ash isn’t smothering the firebox; verify dampers are fully open; consider whether the charcoal is too old or too damp.
• Pellet smokers used as grills: the cooker may not be designed for high-heat searing. Check your model’s max temp spec.
• Built-in grills: gas line pressure may be inadequate. The fix is at the gas supply line, which usually requires a plumber.
• Premium grills: there may be specific safety features that have engaged. Check the manual or call the manufacturer.

A grill cleaning and inspection service is launching in select markets this season — if you’ve worked through the diagnostic and need a pro look, the early list gets first booking.

Frequently asked questions

Why does my regulator keep going into lockout? +

Opening the tank valve too quickly trips the regulator's safety mechanism. The fix is to always open the tank slowly — count to 10 as you open. If the lockout happens repeatedly even with slow opening, the regulator may be failing and needs replacement ($20-40, owner-installable).

How do I know if I need a new regulator vs. just a reset? +

A reset that fixes the problem = no replacement needed. A reset that doesn't fix it, multiple resets needed in short succession, or audible humming/vibration from the regulator = replacement is likely warranted.

Can a low-pressure tank cause permanent damage? +

Not really — the grill underperforms but doesn't suffer damage. Just swap the tank when it's getting close to empty. The 'permanent damage' worry would be running on no propane while igniters keep sparking, which is annoying but not harmful to the grill.

Will cleaning the grill fix the heat problem? +

Sometimes — specifically if the cause is clogged burner ports or venturi tube blockages. A deep clean addresses both at once. If the cause is regulator lockout or empty tank, cleaning won't help. Diagnose first, clean if it's the right fix.

Why does my grill get to 500°F at home but only 350°F at the cabin? +

Usually altitude or tank pressure. Higher altitudes reduce maximum achievable temps slightly. Cold ambient temperatures reduce propane vapor pressure significantly — a tank that performs fine at 70°F may struggle at 30°F. Both are normal; not a grill problem.

Related reading

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  Spider Webs in Your Grill Burner Tubes? Here's What to Do

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