Mr. Heater Buddy: Pilot Lights But Burner Won’t Come On

When a Mr. Heater Buddy pilot lights but the main burner won’t come on, the cause is almost always a fuel-flow problem: low propane pressure from a nearly empty cylinder, a regulator that hasn’t reset, or air trapped in the line after a tank change. HeatersForLife.com walks through the fixes in the order that clears the most units fastest, so the ceramic tile lights and stays lit.

Last Updated: October 2026 | Will Montgomery has an engineering background and troubleshoots portable propane heaters for HeatersForLife.com, so these fixes are checked step by step rather than copied from forums.

Quick Answer

A Buddy heater whose pilot lights but whose burner won’t ignite is getting just enough gas to hold the pilot flame but not enough to fire the main burner. Turn the knob fully to HIGH and hold the ignition a few extra seconds; if the tile still won’t light, the culprit is usually a low or cold 1 lb cylinder, a regulator that locked out during the last connection, or air in a newly attached hose. Bleed the line by turning the heater off, disconnecting and reconnecting the cylinder, and relighting slowly. A burner that lights but drops out after a few seconds points to a dirty pilot or a weak thermocouple signal instead.

Will’s note: If the pilot stays lit but the burner won’t come on, I would check in this order: 1) reset the tank/excess-flow valve, 2) check whether the thermocouple/thermopile is dirty, 3) check the pilot and orifice for cleanliness, 4) check the tip-over switch. And if you’re using a 20-lb tank and hose, slowly opening the tank valve is the first fix I’d try.

Why the Pilot Lights but the Burner Won’t

The pilot only needs a trickle of propane, so it can light on pressure that is far too low to open and sustain the main burner. On a radiant Buddy heater the pilot and the burner are fed from the same valve, but the burner orifice is much larger and demands steady, full-pressure gas. If the cylinder is nearly empty, sitting in the cold, or the regulator has gone into its safety lockout, there is enough flow to keep the little pilot alive but not enough to push gas through the burner orifice and light the ceramic tile. The result is the classic symptom: a healthy pilot flame and a dark, cold burner.

This is different from the “won’t stay lit at all” failure, where the pilot itself dies as soon as the knob is released. That points to the thermocouple or tip-over switch and is covered in the full Mr. Heater Buddy troubleshooting guide.

Fix 1: Set the Knob to HIGH and Give It Time

Many “burner won’t light” complaints are simply a knob left on LOW or PILOT, which never sends enough gas to the main burner. After the pilot is burning, push in and turn the control knob fully to HIGH. On a cold heater the internal parts and the gas itself are chilled, so hold it there for 20 to 30 seconds; the burner tile often blooms to life once the orifice warms and pressure stabilizes. If nothing happens on HIGH, move to the fuel supply.

Fix 2: Check the Propane Supply

A low, cold, or nearly empty cylinder is the single most common reason a Buddy pilot holds but the burner stays dark. Propane pressure falls as the tank empties and as temperature drops, and a radiant burner needs more flow than a pilot. Run through the supply in this order:

• Swap in a fresh 1 lb cylinder or a known-full 20 lb tank. A partly used green bottle is the usual offender.
• Warm a cold cylinder. Below roughly 20 °F a 1 lb bottle struggles to vaporize enough propane. Bring it indoors to room temperature before use — never with a flame or heat gun.
• Confirm the valve is fully open on a bulk tank, and that any inline fuel filter or hose is rated for the heater.

Fix 3: Reset the Regulator and Bleed Air From the Line

Connecting a hose or tank with the valve already open trips the regulator’s excess-flow lockout, which starves the burner even though the pilot still lights. To reset it, turn the heater control knob to OFF, close the tank valve, disconnect the hose or cylinder, then reconnect it snugly. Open the tank valve slowly — a slow open keeps the regulator from locking again. When a hose has just been attached, there is also air in the line; the pilot burns it off quickly but the burner may sputter for a moment. Relight, go to HIGH, and let it purge for 15 to 20 seconds.

Fix 4: Clean the Pilot and Burner Orifice

Dust, spider webs, and lint block the tiny orifices on a portable heater more often than any electrical part fails. A heater stored in a garage or truck collects debris that partially plugs the burner orifice, so gas can reach the pilot but not flow freely to the tile. With the heater cold and disconnected from propane, use compressed air to blow out the pilot assembly and the burner ports. Avoid poking metal into the orifice, which can enlarge it and change the flame. If cleaning restores full flow, the burner will light promptly on HIGH.

The Correct Lighting Sequence

Following the right ignition order the first time prevents most “burner won’t come on” problems before they start. A rushed light-up on a cold heater is what leaves the knob in the wrong position or the line full of air. Do it in this order:

• Connect fuel first, with the control knob OFF. Attach a full cylinder or a hose to a full tank, then open the tank valve slowly.
• Turn the knob to PILOT and press it in. Hold it down while pressing the igniter until the pilot flame catches.
• Keep holding for 30 to 60 seconds. This lets the thermocouple heat up so the pilot stays lit when released. Letting go too soon is the top reason a pilot drops out.
• Turn the knob to HIGH. The main burner tile should bloom within a few seconds. On a cold day, give it up to 30 seconds before deciding the burner is at fault.

If the pilot holds but the tile still refuses to fire after this clean sequence, the problem is genuinely fuel flow or a blocked orifice rather than technique, and the fixes above apply.

When to Stop and Service or Replace

If the supply is full, the regulator is reset, and the orifices are clean but the burner still won’t light, the internal valve or ODS pilot assembly needs service. Portable radiant heaters use a sealed oxygen-depletion-sensor pilot that is not user-rebuildable; a failed one is replaced as a unit. Weigh the repair against the price of a new heater, and never bypass or disable the ODS or tip-over safety to force a light. For safe indoor use of any propane heater, review the ventilation and carbon-monoxide rules in Are Propane Heaters Safe Indoors?

Frequently Asked Questions

Why does my Buddy heater pilot stay lit but the burner won’t turn on?

The pilot needs only a trickle of gas, so it survives on pressure too low to fire the main burner. A nearly empty or cold cylinder, a regulator in lockout, or air in a fresh hose are the usual causes. Fit a full cylinder, reset the regulator, and hold the knob on HIGH for 20 to 30 seconds.

Does cold weather stop a Buddy heater burner from lighting?

Yes. Below about 20 °F a 1 lb propane cylinder cannot vaporize gas fast enough to feed the burner, even though the pilot still lights. Warm the cylinder to room temperature indoors first, or switch to a larger 20 lb tank with a hose.

How do I reset the regulator on a Buddy heater?

Turn the control knob to OFF, close the tank valve, disconnect the hose or cylinder, reconnect it snugly, then open the tank valve slowly. Opening the valve slowly prevents the excess-flow lockout that starves the burner.

Can a dirty orifice keep the burner from lighting?

Yes. Dust and lint partially block the burner orifice so gas reaches the pilot but not the tile. Blow the pilot and burner ports out with compressed air while the heater is cold and disconnected; do not poke metal into the orifice.

Is it safe to keep trying to light a burner that won’t fire?

Brief relight attempts are fine, but stop if you smell a strong gas odor and never disable the ODS or tip-over safety. If the burner will not light after checking fuel, regulator, and orifices, the pilot valve assembly likely needs replacement.