Is Your Gas Fireplace Acting Up?

The inner workings of your gas fireplace probably seem too complicated to understand, and the thought of working on them as likely as performing brain surgery. Take heart: Many of the problems you may experience are simple to troubleshoot and solve. Even if you choose to have a service technician repair your gas fireplace, you'll save money if you can direct him straight to the problem.

One of the most common problems is a gas fireplace that simply won’t turn on. Before you call a repair technician, narrow down the possible causes and determine if it’s something you can fix yourself.

Parts of a Gas Fireplace

There are three main types of gas fireplaces:

A natural vent gas fireplace connects to a metal pipe that runs through the roof.

Direct-vented gas fireplaces vent directly through the wall behind the unit.

Vent-free gas fireplaces do not require a vent.

Regardless of the vent type, a gas fireplace may run on either natural gas or, in certain situations, propane. The ignition type also varies, from a constantly lit, standing pilot light that you ignite with matches to an on-demand pilot that you ignited electronically. Good news for you: The main parts of gas fireplaces are either the same or operate with the same principles. Understanding the terminology and purpose of each will help you troubleshoot your fireplace.

Gas Line: Whether natural gas or propane, the gas line delivers the fuel source into the gas fireplace. A valve on the gas line turns off the gas when the fireplace is not in use. Turning the valve “on” allows the gas to flow and be lit by the pilot light.

Firebox: The firebox contains the flame and fire, which springs from fake logs specially designed for use with gas.

Venting System: As mentioned above, gas fireplaces may vent through the roof or a wall, or require no venting. The vent is simply the chimney. In vented systems, the flue (another name for chimney pipes) has two purposes: It provides air to feed fire combustion and allows dangerous gasses to escape. Vent-free gas fireplaces use different technology to eliminate the need for oxygen and gas release and will not experience vent problems associated with natural and direct vent units.

Blower Fan: Not every gas fireplace has a fan, but those that do circulate the heat more effectively. An internal fan, driven by electricity, cycles the air and blows it out of the fireplace much like a furnace generates heat.

Pilot Light/Ignition System: Regardless of the type of pilot light — standing or electronically ignited — all gas fireplaces must light and remain lit to generate heat. A standing pilot light is lit like an old furnace, by turning on the gas and introducing a flame. Electronic ignition relies on a spark to light the gas instead. A few parts make either ignition method possible. These are the gas supply and valve already mentioned, a thermocoupler, a thermopile and sometimes a piezo – a push button that lights a standing pilot so you don’t have to use a match. Together, these parts light and maintain the pilot as well as control the burner.

Thermocoupler and Thermopile: Once the pilot is lit, it heats up a thermocoupler and a thermopile. The thermocoupler, sometimes referred to as a heat or flame sensor, is made from two different metals that create a small electrical charge when heated by the pilot. This electrical current causes a magnet in the gas valve to shift open, allowing gas flow. If the pilot isn’t lit, the magnet shifts again, causing the gas valve to close. In essence, the thermocoupler is a safety mechanism. Likewise, the thermopile is a system of thermocouplers that create a greater electrical current, moving a larger magnet that allows gas to flow through the main gas line into the burners.

Troubleshooting a Gas Fireplace: Problems and Fixes

A note of caution: Due to the differences in models and operating styles, it’s impossible to cover every situation that may arise. Additionally, some repairs are complex and require a professional’s knowledge and tools. Finally, gas and electrical components require caution during inspection, repair and operation. Follow the proper safety measures around your gas fireplace at all times. That said, some of the most common problems are simple to find and fix by the average do-it-yourselfer.

Gas Fireplace Won’t Ignite:

One of the most common problems is a gas fireplace that simply won’t turn on. Before you call a repair technician, narrow down the possible causes and determine if it’s something you can fix yourself.

If the fireplace operates with the flick of a light switch or if it contains an electronic ignition, it’s worth checking the house fuse or breaker box. Ideally, the fireplace is alone on a breaker or with very few other items. An overloaded circuit can easily blow (fuse) or trip (breaker). Check the fuse and replace as necessary, or turn the proper breaker completely off, if it is positioned halfway between off and on, and then back on again. Sometimes this will solve the problem without further fuss or need of professional assistance. Also, most manufacturers provide means to light the pilot without electricity, such as with a battery pack or match, in case of emergency. Consult your product literature for further information.

Without fuel, the pilot light can’t ignite. Another simple fix is a lack of gas. Check to see if the gas valve is open, and open it if necessary. If this fails to solve the problem, check your fuel supply itself. Does your propane tank have gas, or is the natural gas supply to your home operating? Eliminate fuel problems before proceeding to pilot light failure troubleshooting.

Pilot Light Failure:

Sometimes the pilot light has simply blown out. If a visual inspection shows no flame, try lighting your pilot again. Follow the manufacturer’s instructions precisely. Bypass an electronic ignition, if necessary, with a manual lighting method.

In some instances, a strong draft may have blown out your pilot light. Simply relighting your pilot should solve the issue at least temporarily, but if it happens again, check your fireplace vent cap. Ensure it is present, secure and lacking holes or gaps that may cause a downdraft. Repair or replace as necessary. Perform a total chimney inspection and cleaning at this time to eliminate the need to do it later in the heating season.

Look over the wiring that leads to the pilot light system, if the fireplace still refuses to light or stay lit. Check for loose or unconnected wires or wires that look black, melted or otherwise damaged. While you may be able to reattach loose wires, never attempt to repair damaged ones. Under normal operating conditions the wires will not get damaged, so their presence indicates deeper fireplace issues. Consult a service technician for professional assistance.

When the pilot light acts like it wants to light but quickly goes out again, the problem may be a weak thermopile. Every gas fireplace uses a thermopile, and after a few years they may go out. This is generally another repair best left to a professional.

Fireplace Burner Issues:

The ignition system doesn’t merely light the pilot, it also powers the burners that stay lit during the heating cycle. If the burner refuses to light or fails to work properly, perhaps acting sluggish or stubborn, try narrowing down the problem to determine your next logical step. Unless you have experience, most internal parts are best serviced or replaced by a professional.

Is the thermostat set high enough to create a demand for heat? As simple as it sounds, some gas fireplace owners may overlook the thermostat and think the fireplace is malfunctioning when, in truth, it simply isn’t set to the proper temperature.

A dirty pilot light orifice – the area from which the flame emerges – or dirty burner jets may cause problems with either the pilot light flame or burner operation. A service technician may clean and remove soot, dirt and other contaminants that clog the system.

One of the most common causes of burner failure is due to loose or faulty wiring. Visually inspect the wiring, looking for unattached or obviously damaged wires running from the pilot light assembly. Consult a professional for wiring assistance.

As mentioned, the ignition system relies on generating an electrical current to open and close the gas valve, allowing fuel to flow to both the pilot and the burner. Other electrical circuits run to the appliance switch and thermostat. Low voltage to any of these parts can lead to a poorly functioning or inoperable burner. A service technician can quickly and easily test the circuitry and diagnose the exact problem.

Another problem that can cause burner issues is a malfunctioning thermocoupler. As with a thermopile, thermocouplers may wear out and need replacement after a few years, or may simply not fit tightly inside the valve. A professional can easily test and resolve the problem for you.

Strange Odors:

Regardless of vent type, you shouldn’t experience any strange or unpleasant odors. If you do notice a smell, it’s likely caused by one of a few things.

Dust and dirt, settled on the burner or other internal parts, can create an odd odor. This is especially common in ventless gas fireplaces, which have no other means of escape for contaminants. Cleaning the fireplace, as instructed by the manufacturer or as performed by a service technician, will usually remedy the problem. A professional can also address the cause of excessive dirt and soot.

When the flue is full of dirt and debris, it may cause a funny smell in vented gas fireplaces. Combustion gasses may back up into the fireplace and the flame itself may starve for oxygen. The solution is simple: Remove any chimney obstructions and clean the flue as necessary. A professional chimney service will make short work of the task, or you can do it yourself.

The smell of burning wiring is hard to describe, but distinct. Once you smell it, you never forget. If you notice an odd, plastic-like smell, immediately disconnect your fireplace, turn off the gas supply and consult a professional.

Natural gas and propane have little to no smell. Gas companies add an ingredient that emits a distinct odor. If you smell what you suspect is gas, immediately turn off the gas supply, open up your windows and vent the house completely. Before attempting any further troubleshooting, contact a service professional, or even your utility company representative, for assistance.

Strange Sounds:

Some noises may be normal for your fireplace. If the sound isn’t new and your gas fireplace acts fine, you have little cause for alarm. New sounds, coupled with operating issues, are clues that the two are related. Try to pinpoint the exact sound and, if possible, from where it originates. Contact a service professional for more intensive troubleshooting and repair.

A low, rumbling sound that occurs when only the pilot light is on may indicate a poorly adjusted flame.

The same roaring sound, with the burners on, often indicates dirty burners.

A grinding or shrieking noise may come from a blower, if your gas fireplace has one.

An Abundance of Soot:

You may instinctively think that since your gas fireplace doesn’t burn wood, you won’t have problems with a dirty fireplace or soot in the chimney. Unfortunately, it isn’t true. Try to reduce the amount created to protect your family’s health and to avoid a fire hazard.

Does your gas fireplace create beautiful, dancing yellow flames? While it’s the most natural looking flame, if you want the wood burning effect, it’s also rich in soot. Soot is, after all, the product of unburned fuel and a soot-rich flame contains too much fuel and too little oxygen. Thus, the fuel doesn’t burn completely. Adjusting the air setting, according to the manufacturer’s instructions, will increase the oxygen flow and lead to an energy efficient blue flame instead. A qualified service professional can easily adjust the air-to-gas ratio and verify the amount with special equipment.

If the flue is blocked with a bird’s nest, leaves or other obstruction, gasses from unburned fuel cannot escape easily and may coat the lining. As the chimney becomes more blocked, it will accumulate on the gas fireplace interior as well. The solution is a complete chimney inspection, blockage removal and cleaning.

Inspecting and Maintaining Your Gas Fireplace

As convenient and efficient as a gas fireplace is, it requires a little attention to ensure it remains safe and trouble-free. The Hearth, Patio and Barbecue Association recommends that you have your gas fireplace professionally inspected and serviced at least once a year. A professional annual inspection includes cleaning the burners and pilot light assembly, checking the safety systems and testing the ignition system. The flue is also closely inspected to spot loose connections and leaks, obstructions, such as bird’s nests and leaves, and cleaned to remove dangerous soot. Another good practice is to install a carbon monoxide detector, in addition to smoke detectors, and replace the batteries during an annual safety inspection. Routine maintenance and repair will ensure your gas fireplace keeps you cozy and comfortable for years to come.