A patio heater that won’t light is almost always short of gas or missing its spark: an empty or locked-out propane tank, a closed valve, a dead igniter, or a pilot tube blocked by a spider web. A heater that lights and then goes out when you let go of the knob has a different fault. Its safety circuit, the thermocouple and the tilt switch, isn’t proving the flame, so the gas valve closes on purpose.

Notice which of the two yours does before you change anything. Here is the order our technicians work through on a service visit in Los Angeles, the checks that are safe to do yourself, and the point where a homeowner should stop.

Before you touch anything

Turn the control knob to off and close the gas, at the tank valve on a propane heater or at the shut-off on a natural gas one. Then let the head cool completely. The emitter screen and the reflector stay hot long after the flame is gone.

If you smell gas, stop there, and never look for a leak with a flame. Close the tank valve if you can reach it safely, keep flames and sparks away, and step back. If the smell is strong or hasn’t cleared after a few minutes, propane or natural gas, leave the area and call 911 or your gas utility’s emergency line from a safe distance.

When a patio heater won’t light at all

Start with the gas supply.

• Tank level. Lift the tank. One that feels light is close to empty, and it can still feed a pilot while having nothing left for the main burner.
• Tank connection. The regulator’s coupling nut should be hand-tight on the tank valve. Brush soapy water on it with the tank open and the heater off. Bubbles mean a leak, so close the tank and leave it closed.
• Regulator lockout. Propane tanks and regulators have an excess-flow safety that chokes the gas down to a trickle when a tank valve is spun open fast. To reset it, turn the heater knob to off, close the tank valve, unscrew the regulator, wait a minute, reconnect it, and open the tank valve slowly.

Next comes the spark. Push the igniter button and listen. A piezo igniter makes one sharp click per push and needs no battery. A battery igniter ticks quickly and hides an AA or AAA cell under the button cap, so swap that first. Then watch for a blue spark at the pilot while you press. No spark with a fresh battery usually means a cracked electrode or a wire that has come loose. If the pilot doesn’t catch after a few tries, turn the knob to off and let the gas clear for five minutes before trying again.

Gas and spark both there, and still no pilot flame? Spiders nest in pilot tubes and burner air inlets over the summer, and a web you can barely see is enough to block the pilot orifice. With the gas off and the head cool, blow the pilot area out with canned air or a soft brush. Don’t push a pin or a wire into the orifice. Enlarging that drilled hole changes the flame for good.

It lights but won’t stay lit when you release the knob

While you hold the knob in, you are holding the gas valve open by hand. The thermocouple, a thin metal probe in the pilot flame, is supposed to take over. Once it’s hot it makes a tiny electrical current that keeps a magnet inside the valve energized. Let go too early, or let the probe run cool, and the gas stops.

So hold the knob for the time your manual gives, commonly half a minute to a full minute. If the pilot still drops out, study the flame. It should be steady, mostly blue, and wrapped around the top of the thermocouple. A small or yellow flame that only brushes the probe points back to a dirty pilot orifice or low gas pressure. A strong flame on a probe that still won’t hold means the thermocouple is worn out, sooted over, or loose at the valve.

Tall heaters carry a second guard in the same circuit. The tilt switch, also called the tip-over switch, opens when the heater leans too far and shuts the gas off if the unit goes over. On uneven pavers or a sloped deck it can read a standing heater as a falling one, so move the heater to flat, level ground and try again. A corroded switch or a broken wire does the same thing on level ground and has to be replaced.

Never bypass a tilt switch, and never wedge or tape the knob to get around a thermocouple. Either trick leaves you with a heater that keeps releasing gas when there’s no flame to burn it.

The flame dies after a few minutes

Wind is the usual suspect. A gust pushes the pilot flame off the thermocouple for a few seconds, the probe cools, and the valve closes. On breezy nights, shelter the heater behind a wall or fence and keep the clearances in your manual from anything that can burn.

A tank that is running low looks similar, and you may see frost on the outside of it.

Check the head as well. The burner screen should glow evenly. Black soot on it, yellow flames above it, or a sharp exhaust smell mean the burner isn’t getting the right mix of air and gas. Leave it off until it has been cleaned. A missing or bent reflector won’t put the flame out, but it sends the heat up instead of down, so a heater can burn well and still leave the table cold.

Natural gas and mounted heaters

A natural gas heater has no tank to run dry. Find the shut-off valve on the supply line. The handle sits in line with the pipe when the valve is open and across it when closed. If other gas appliances at the property are out too, the problem is upstream of the heater.

Heaters mounted on a wall or under an eave usually light from a wall switch or a remote. A control module opens the valve, fires the igniter, and has to sense flame within a few seconds or it locks out. Some older units use a thermopile instead, a heavier relative of the thermocouple that produces enough current to run the gas valve. On these and on electric heaters, start at the breaker and the wall switch.

Where a homeowner should stop

Tank level, a regulator reset, the igniter battery, a clean pilot area and level ground are the homeowner’s share. Past that, put the tools down.

• A gas smell that comes back after you have tightened the tank connection.
• Any repair that means opening the control valve or replacing the regulator, the hose, the thermocouple, or the pilot assembly. Those joints have to be leak-tested afterward.
• Anything on a natural gas line, from the shut-off back to the meter.
• Soot, yellow flame, or a heater that has tipped over or been scorched.

Heaters on a restaurant patio

A restaurant or bar runs its heaters for hours every night, so thermocouples, pilot assemblies, igniters and hoses wear sooner. If you manage a row of them, tag the one that fails and write down what it did before staff start swapping tanks around. We handle commercial patio heater repair for restaurants and bars.

Getting a technician out

BBQ Repair Doctor is family-owned and has been repairing outdoor gas equipment for 30+ years. Our certified technicians do patio heater repair in Los Angeles County and Ventura County on tall propane heaters, natural gas heaters, wall and eave-mounted units, and electric models, at homes and on restaurant patios. You get a firm quote before any work starts, and the repair carries a warranty on parts and labor.

Pilots and thermocouples do the same job inside gas fire features. If the trouble is in the fire bowl or the hearth next to the heater, we also do fire pit repair and outdoor gas fireplace repair.

Call 818-392-8666 and tell us what the heater does when you try to light it. Same-day appointments are offered when the schedule allows.

Common patio heater questions

Why does my patio heater pilot go out when I release the knob?

The thermocouple isn’t holding the gas valve open. Either the knob was released early, the pilot flame is too small to heat the probe, or the probe or the tilt switch wired with it has failed. A meter test shows which.

Why won’t my heater light after I changed the propane tank?

Two things happen at a tank swap. The hose fills with air, so the pilot needs a longer hold before gas arrives, and opening the new tank quickly can trip the regulator’s excess-flow safety. Close everything, disconnect and reconnect the regulator, then open the tank valve slowly.

Is it safe to bypass the tilt switch or the thermocouple?

No. Those two parts shut the gas off when the flame goes out or the heater falls over. Replace the failed part and keep the protection.

Can I use a patio heater in a garage or an enclosed patio?

No. Fuel-burning patio heaters give off carbon monoxide and need open air around them, so never use one indoors or in an enclosed space such as a garage or a closed-in porch. For a covered area, ask about a heater that is listed for that kind of installation.