Gas Fireplace Pilot Light on But Wont Start

Gas fireplaces are an excellent way to cozy up in your home, plus they’re easy to use and extremely cost-effective.

But, there can be issues with them too. One of the most frequent issues is when your gas fireplace pilot light will illuminate but won’t start.

Check the Thermocouple

When your gas fireplace’s pilot light won’t stay lit, it could be indicative of a failing thermocouple. This small metallic sensor sits near the flame and detects heat in its vicinity; when activated, it allows gas to flow into the firebox to ignite if necessary.

Thermocouples can be constructed out of materials such as nickel-chromium or iron. When heated, their two wire legs create a junction which allows them to measure the temperature of surrounding air or flames. Once warmed up, this cold part generates an electric current which can then be measured and used for controlling a gas valve’s operation.

This type of sensor is often found in residential gas appliances like furnaces and water heaters. To test a thermocouple, use a multimeter to check its output for millivolts produced. If it produces 25 millivolts or more, then your thermocouple appears to be working properly; otherwise, replacement is necessary.

Next, test the thermocouple by heating one end that keeps in contact with a pilot flame using a cigarette lighter. This should look needle-shaped and appear to absorb heat. After it has warmed up, screw one lead onto either side of device and another onto the end that screws into the gas valve.

If the resistance of the test lead is excessively high, such as 40 ohms or higher, then your thermocouple does not have continuity and won’t function. This test should only be conducted by a certified professional to guarantee accurate results.

Thermocouples feature two test leads: a positive lead and a negative lead. The positive lead is the same color as the hot end of the thermocouple, while its opposite is colored to match its cold end.

To test a thermocouple for resistance, attach the positive lead to the end that screws into the gas valve and the negative lead to its exposed end. Select either ohms or resistance on your multimeter before connecting another test lead to that other end and holding a torch or lighter over it for several minutes.

Clean the Igniter

If you own a gas fireplace, it’s essential to know how to properly clean the igniter when the pilot light has gone out. Doing this can help avoid serious damage to the fireplace and expose your home to toxic fumes from burning fuels.

The initial step in cleaning an igniter is to make sure it’s free from dust, dirt and other obstructions. Clogging up the igniter can negatively affect its operation and even lead to malfunctioning.

Before beginning this task, make sure you have the necessary tools and materials. A stainless steel brush and fine-grit sandpaper can be used to scrape away any built up debris.

Another essential step is to blow compressed air into the pilot tubing and wait a few minutes before trying again. This will rid any air that has clogged up the tube.

If the pilot won’t light, you may need to replace the spark igniter. This is where the battery goes in to generate sparks that ignite the flame.

Finally, test the thermocouple and thermopile to make sure they are functioning correctly. This will guarantee your gas valve is detecting temperature changes and producing electricity to ignite the pilot light when needed.

A malfunctioning thermocouple or thermopile can cause your fireplace to malfunction. Usually, this occurs because the probes have become blocked with carbon deposits from burning continuously.

However, it could also be due to insufficient gas pressure. This will diminish the efficiency of your flame and cause your gas fireplace to malfunction.

One of the best ways to test gas pressure is by calling a professional. They can do a quick inspection and verify that your pressure is set correctly.

You could also try adjusting the thermostat on your gas fireplace to see if that helps. This is a great idea if you want an energy-saving way to heat your home.

Be sure to ensure the fuses and breakers in your home aren’t being overloaded. A gas fireplace could potentially trip a breaker if it isn’t on its own breaker and sharing power with other appliances.

Clean the Burner

If your gas fireplace is not staying lit, there could be several potential causes. Fortunately, most of these issues can be solved without professional assistance.

First, test the pilot light to confirm it’s functioning properly. If so, the issue likely lies with one or more sensors connected to it: thermocouple and thermopile.

Thermocouples use an electric current to detect whether a pilot light is hot or not. Without heat detection, your pilot light won’t illuminate.

Once the thermocouple detects heat, it will send a signal to the ignitor module that causes it to fire. If your ignitor does not light, you may need to replace either its battery inside or the entire box itself.

Alternately, the problem could lie with the spark igniter itself. To check this, set the control knob to “Pilot” and push in on the ignitor all the way. If you see a spark from it toward the pilot light, either its battery has failed or needs replacing.

Another possible culprit is a clogged burner port, which may be due to debris like grease or food crumbs blocking gas flow to the igniter. If your burner port is blocked, it may take an extended period for your pilot light to come on.

Another possible explanation for why your gas fireplace pilot light may be illuminated but won’t light is a blocked air draft. To resolve this problem, try purging air from the vent cap or install a draft stopper to prevent it from occurring again.

The most common cause for pilot light failure is a dirty pilot orifice. Cleaning this area with a hand brush, rag and vacuum cleaner is an effective and inexpensive fix that can save you a lot of time and hassle in the future.

Check the Gas Valve

When your gas fireplace pilot light won’t start, the first thing to check is your gas valve. A malfunctioning valve poses a serious safety risk; thus, contact your local gas company or an engineer for inspection before attempting any fixes yourself.

If the gas valve is working fine, the issue could be with your thermocouple or thermopile which generates the small amount of voltage that signals the main valve to remain open. In such a case, you should replace these parts immediately.

Another possibility is that the circuit to your gas fireplace has become overloaded, preventing it from getting enough power to start. This could occur due to dirty or corroded connections at the house’s wiring box; thus, testing the voltage supply with a voltage tester or resetting any tripped breakers will restore power to the system.

One way to check if your thermostat is sending the correct voltage to your gas fireplace is by using a thermocouple or thermopile. You may also use an ohmmeter and test the coils for resistance.

It’s also possible that something has blocked the gas tube from your pilot light, so this should be carefully examined. Dust and insects can build up inside pipes, so make sure all debris has been removed and cleaned before trying to relight your pilot.

A bubble of air that has built up in the pipeline could also be responsible for this issue; to clear it out with either a vacuum cleaner or compressed air. Once this is done, you should be able to relight your pilot and restore full gas flow once more.

If you find that you have an air lock, try pressing on the gas valve knob to release the bubble and see if that helps light your pilot again. If not, it could be that it’s time for a replacement pilot light.

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