How a patio heater stays lit
Most gas patio heaters, the tall mushroom style and the pyramid glass tube style, work the same way. You push in the control knob to let gas flow to the pilot, light it with the igniter, and keep holding the knob while the pilot heats a thermocouple. Once the thermocouple is hot, it holds the safety valve open and you can release the knob and turn up the main burner.
Many heaters also have a tilt switch (sometimes called an anti-tilt device) that cuts the gas if the heater leans or tips. Some also have an oxygen depletion sensor. Any of these can shut the heater off if something isn't right.
When it goes out, and what it usually means
| When it goes out | Most likely causes |
|---|---|
| As soon as you release the knob | Didn't hold long enough, thermocouple not in the pilot flame, dirty or failing thermocouple, weak pilot |
| A few minutes after lighting | Wind blowing out the pilot or cooling the thermocouple, low tank, tripped regulator |
| After running a while on propane | Tank getting low or icing up in cool weather |
| Randomly, or when bumped | Tilt switch triggered by uneven ground or a loose switch |
| Won't light at all | No gas, dead igniter, blocked pilot orifice (often spiders), wet igniter |
Checks you can do safely
Do these with the heater turned off and cool, outdoors, away from anything flammable.
- 1
Check the gas
For propane, weigh or shake the tank to estimate fill, and make sure the valve is fully open. For natural gas, confirm the shutoff is open. A low tank often lights the pilot but can't sustain the main burner.
- 2
Reset the regulator
On propane heaters, turn everything off, close the tank, disconnect and reconnect the regulator, then open the tank valve slowly. This resets the flow limiter.
- 3
Hold the knob longer
Hold the knob in for 30 to 60 seconds after the pilot lights, or as long as the manual says. A cold thermocouple needs time.
- 4
Check the tilt switch
Make sure the heater is on level, solid ground. If it was recently moved or bumped, the tilt switch may be sensitive; level the base and try again.
- 5
Look at the pilot and thermocouple
With the reflector or access panel off (if your model allows), look at the pilot assembly. The thermocouple tip should sit in the pilot flame. Look for spider webs, soot or corrosion.
- 6
Shield from wind
Try lighting in a sheltered spot. If it stays lit there, wind was the issue.
The thermocouple is the usual culprit
If the heater lights but won't stay lit when you release the knob, and the gas supply checks out, a worn or dirty thermocouple is the most common cause by far. They're inexpensive parts, but they connect to the gas valve and need to be positioned correctly in the pilot flame. A misplaced thermocouple can make the heater cycle on and off. A repair visit typically includes cleaning the pilot assembly, replacing the thermocouple if needed, and checking the valve. Our thermocouple and safety valve page covers that repair in more detail.
Spiders deserve their own mention. Heaters that sit unused through the warmer months are a favorite spot for webs in the pilot tube and orifice, which starves the pilot of gas or air. A blast of compressed air or careful cleaning often fixes it. See spiders in burner tubes for why this happens.
Seasonal care
- Before the cool season, clean the reflector, emitter screen and pilot area.
- Check the hose and regulator for cracks or brittleness.
- Make sure the base sits level and the tilt switch isn't damaged.
- Cover the heater when not in use, or store it somewhere dry.
- Clear spider webs from the pilot assembly and air openings.
- In coastal homes, wipe down the post and reflector regularly to slow corrosion.
Common questions
My heater stays lit on low but goes out on high. Why?
Often a low tank or a regulator that isn't delivering full flow. In cool weather, a nearly empty tank can't vaporize propane fast enough for high output.
Can a patio heater be converted from propane to natural gas?
Some models can with the manufacturer's conversion kit; many cannot. Check with the manufacturer first. Our gas conversion page has more detail.
Do you repair patio heaters?
Yes, including freestanding, wall-mounted and table-top gas heaters. See patio heater repair.
Is it normal for the emitter screen to glow unevenly?
A little variation is normal. Large dark patches or a screen that glows only on one side can mean a burner blockage, low gas supply or wind. Have it checked if it doesn't even out after warming up.
Can I leave a patio heater outside all year?
Many are designed for outdoor use, but a cover and occasional cleaning help a lot, especially near the coast where salt air corrodes the post, burner and fasteners.
Related guides and repairs
Fire Pit Won't Light
A safe, step-by-step troubleshooting guide for gas fire pits that won't light or won't stay lit, from gas supply to ignition and thermocouples.
SafetyGas Fireplace Maintenance
Routine care for indoor and outdoor gas fireplaces, what homeowners can safely do, and the warning signs that call for a technician.
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.
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.
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.
RepairThermocouple & Safety Valve
Burners that go out when you release the knob: thermocouples and flame safety valves tested and replaced.
RepairRegulator & Hose Replacement
Worn propane regulators, cracked hoses and tired natural gas flex connectors replaced and leak tested.
RepairSpider & Insect Blockages
Spider webs and insect nests in burner venturis cleared before they cause weak flame or a flashback fire.
RepairNatural Gas & Propane Problems
Supply-side problems on propane and natural gas grills: wrong orifices, undersized lines, regulators and bad conversions.
Heater still giving up?
Send us the model tag and a short description of when it goes out, and we'll set up a repair visit.