Check the thermocouple first: clean it, align it in the pilot flame, and test. If the pilot stays lit but the burner doesn't ignite, inspect the igniter and gas flow.
A patio heater that won't light or keeps shutting off can ruin an evening outdoors. But before you call a technician, know that most common issues have simple fixes. Our editorial team compared specifications, buyer feedback, and key decision factors to bring you a practical troubleshooting guide. You'll learn how to diagnose pilot light problems, gas flow issues, igniter failure, and thermocouple faults, step by step.
Why It Happens: The Four Usual Suspects
Patio heaters are simple machines, but they rely on a precise sequence: gas flows, igniter sparks, pilot flame lights, thermocouple senses heat, gas valve opens, burner ignites. If any step fails, the heater won't work. The most common culprits are:
- Thermocouple fault: This safety device shuts off gas if the pilot flame goes out. If it's dirty or worn, it may not generate enough millivolts to keep the gas valve open, causing the pilot to go out.
- Pilot light problems: A clogged pilot orifice, a draft, or a misaligned thermocouple can prevent the pilot from staying lit.
- Igniter failure: A weak or absent spark means the piezo igniter or electrode is dirty, damaged, or disconnected.
- Gas flow issues: Low gas pressure, a closed valve, a kinked hose, or an empty tank can starve the heater of fuel.
Identifying which one you're dealing with is the first step to a fix.
How to Fix: Step-by-Step Troubleshooting
1. Check the Gas Supply
Before anything else, make sure the gas tank has fuel. If you have a propane tank, you can check the level by pouring warm water down the side; the tank will feel cool where gas remains. Also verify that the valve on the tank is fully open (turn counterclockwise). If you have a natural gas heater, confirm the shutoff valve is open and the supply line isn't kinked or blocked.
2. Inspect the Igniter
Turn the control knob to the pilot position and press the igniter button. You should hear a clicking sound and see a spark near the pilot electrode. If you see no spark, remove the electrode and clean its tip with fine sandpaper or a wire brush. Ensure the electrode gap is about 1/8 inch from the pilot hood. Check the wire connecting the igniter to the electrode; it may be loose or corroded. If the spark is still weak or absent, the piezo igniter may need replacement.
3. Clean the Pilot Assembly
If you have a spark but the pilot doesn't light, the pilot orifice may be clogged. Turn off the gas, remove the pilot assembly, and clean the orifice with a thin wire or compressed air. Also check the pilot tube for blockages. Reassemble and try again.
4. Test the Thermocouple
If the pilot lights but goes out when you release the control knob, the thermocouple is likely not sensing the flame. Ensure the thermocouple tip is positioned in the pilot flame, not just near it. Clean the tip with fine sandpaper to remove soot or oxidation. If it still fails, you can test it with a multimeter: with the pilot lit, the millivolt reading should be around 25 to 30 millivolts. If it's lower, replace the thermocouple.
5. Check the Burner and Venturi Tube
If the pilot stays lit but the burner doesn't ignite when you turn the knob to high, the burner ports or venturi tube may be clogged with debris, spider webs, or rust. Turn off the gas, remove the burner, and clean the ports with a wire brush. Check the venturi tube for blockages and clear them with a long brush or compressed air.
When to Replace vs. Repair
Some parts are cheap and easy to replace, while others are better left to a professional. Here's a quick guide:
- Thermocouple: Usually under $20 and easy to swap. If cleaning doesn't work, replace it. It's a common wear item.
- Igniter: A new piezo igniter is also inexpensive and can be installed with basic tools. If the spark is weak, replacement is the fix.
- Gas valve or regulator: These are safety-critical components. If you suspect a faulty gas valve or regulator, do not attempt repair. Call a licensed technician.
- Burner or heat shield: If the burner is rusted through or warped, replace it. This is a doable DIY job, but ensure you get the exact model.
If you smell gas at any point, turn off the gas supply immediately, ventilate the area, and call a professional. Do not use the heater until it's inspected.
Preventive Maintenance Tips
To avoid future issues, follow these simple habits:
- Clean the burner and pilot assembly at the start of each season.
- Inspect the gas hose for cracks or wear, and replace if needed.
- Store the heater with a cover when not in use to keep out debris.
- Check the thermocouple and igniter annually for corrosion.
- Always turn off the gas at the tank after use.
Regular maintenance not only extends the life of your heater but also ensures safe operation.
When to Call a Professional
While many fixes are DIY-friendly, some situations require a certified technician:
- Gas smell or suspected gas leak.
- Faulty gas valve or regulator.
- Internal wiring issues that you can't diagnose.
- Heater is under warranty; DIY repairs may void it.
If you're ever unsure, err on the side of safety. A professional can diagnose and repair issues quickly, and the cost is often worth the peace of mind.
By following this guide, you'll be able to fix most common patio heater problems yourself. Remember to always prioritize safety and follow your manufacturer's instructions. For replacement parts, check the current price on Amazon.