Gas Fireplace Burner Assembly Parts Labelled

Parts Of A Gas Fireplace (Explained With Real Examples)

In Gas Fireplaces by James O'KellyLeave a Comment

Gas fireplaces are designed to imitate the look and feel of other types of fireplaces such as wood burning, but behind the flames and the faux logs are a number of components that help a gas fireplace burn the fuel safely and efficiently.

The main parts of a gas fireplace can include:

  • The frame/firebox
  • Faux media, such as logs, coals or pebbles
    • Combustion matrix
  • Cover, such as a firefront
  • Burner assembly
  • Burner
  • Controls
  • Ignition
    • Thermocouple
    • Thermopile
    • Spark electrode
    • Pilot burner/flame
  • Gas supply pipe with valve
  • Firebox liner
  • Venting arrangements
Gas Fireplace Parts Labelled
Gas Fireplace Burner Assembly Parts Labelled

Other parts of a gas fireplace that can vary depending on the type of fireplace can include:

  • Hearth
  • Surround
  • Oxygen Sensor
  • Blower
  • Wall switch
  • Remote control
  • Cable fixings

Although there are three main types of gas fireplace, which include natural (b-vent), direct vent and ventless, they all share a large number of similar components between them.

Our own gas fireplace is a natural vent insert, which we’ve used throughout this article to explain the main parts of a gas fireplace as well as to explain what the parts of a gas fireplace are called.

Gas Fireplace
Our current gas fireplace

We’ve also recently removed an old gas insert from our kitchen fireplace, which we also use to explain parts.

Gas Insert With Surround
An old gas fireplace that we recently had removed

Main Parts Of A Gas Fireplace

Frame & Firebox

The frame of a gas fireplace is the outer shell in which all of the other main parts sit.

The look and size of the frame for a gas fireplace will vary depending on the type of gas fireplace, the manufacturer and the model. When installing a gas fireplace, you’ll want to take the size and shape of this frame into account.

As an example of a typical insert frame, the pictures below show what our old gas insert looks like from all angles.

Gas Fireplace Insert Removed
The front of our old gas fireplace insert
Gas Fireplace Insert Back
The back of our old gas fireplace insert

The firebox can be considered to be the main area inside the frame of a gas fireplace, where the media and flames are located.

The image below shows the firebox of our current gas fireplace.

Gas Fireplace
The firebox located within the frame of a gas fireplace

Fireplace Media

The media of a gas fireplace is part that helps a gas fireplace to imitate the look and feel of other types of fireplace.

This gas fireplace media is commonly found in the form of:

  • Logs
  • Coals

Other gas fireplace media can include pebbles and other materials, but logs are typically the most common gas fireplace media effect.

Media is required otherwise a gas fireplace would simply consist of flames.

A gas fireplace burns gas as the source of fuel and so the media in a gas fireplace isn’t real.

Instead, the media such as a log effect media are made from non-combustible materials such as ceramic.

Our gas fireplace has a coal effect media.

Gas Fireplace Coals
Gas Fireplace Coals
Gas Fireplace Coal

These pieces of ceramic are designed to look like a coal fire when arranged together inside the fireplace.

For our particular model of gas fireplace, these coals sit on top of a combustion matrix; also made from ceramic.

Gas Fireplace Combustion Matrix
The combustion matrix located underneath the coals

The combustion matrix helps bring the individual coals up from the burner assembly inside the fireplace below. A combustion matrix may not be found in all types of gas fireplace but helps provide some height to the faux coals in our own fireplace.

Gas Fireplace Combustion Matrix
The underside of the combustion matrix


Depending on the type of gas fireplace, it will typically have some sort of cover or frame that hides the internal components out of view.

Many direct vent gas fireplaces can have a frame cover that can be removed or opened to access the controls, with an example shown below.

An example of removing the cover frame to access gas fireplace controls

Our own natural vent gas fireplace insert has a firefont, which acts both as a cover and as a decorative feature.

Gas Fireplace Firefront
The cover on our gas fireplace comes in the form of a firefront

This cover comes in two separate pieces, both of which aren’t directly attached the main gas fireplace unit but instead stand up separately on the hearth.

Gas Fireplace Firefront
Gas Fireplace Firefront
Gas Fireplace Firefront

Certain types of gas fireplace that require the air within the fireplace to be kept separate from the air within the room, such as direct vent gas fireplaces, will typically have a glass front in which to view the flames through.

Direct Vent Gas Fireplace
Many gas fireplaces have glass fronts

As our gas fireplace is a natural vent version it doesn’t have a glass front but is open to allow air from within the room to be used to supply the fire.

Burner Assembly

The burner assembly, which can also be referred to as simply the burner, is the main functional part of a gas fireplace and is where the flames are generated.

It typically sits at the base of a gas fireplace located underneath the fireplace media and behind any cover/firefront.

The burner assembly is made up of a number of smaller components, which we discuss individually further in this article, and typically includes:

  • Burner tray
  • Ignition, including pilot
  • Controls

The burner assembly inside our current gas fireplace sits at the base of the unit and is held onto the main frame of the fireplace with screws.

Gas Fireplace Burner Assembly
The burner assembly of our gas fireplace insert
Gas Fireplace Burner Tray
Top view of the burner assembly

The pictures below show the burner assembly removed from our old gas fireplace insert for a better idea of what a burner assembly looks like.

Gas Fireplace Burner Assembly
Examples of another burner assembly
Gas Fireplace Burner Assembly
Gas Fireplace Burner Assembly


The burner of a gas fireplace, which may also be referred to as the burner tray, is the area at the top of the burner assembly where the main flames are produced.

The burner can come in a range of designs but the burner in our gas fireplace looks much like a tray.

Gas Fireplace Burner Tray
The burner tray at the top of the burner assembly

The burner can have a number of holes to generate the flames across the width of the fireplace.

Gas Fireplace Burner Tray

The burner will be fed with a gas supply from below.

Gas Fireplace Controls
Gas is fed to the burner tray from below, behind the controls

The size of the flames generated by the main burner can be adjusted using the controls on a gas fireplace, and the main burner flames can be started using the pilot.


The controls on a gas fireplace are what can be used to start and adjust the flames.

The control for our current gas fireplace insert is shown below and consists of a singular dial.

Gas Fireplace Control Dial
Gas Fireplace Control Dial

With this dial we can:

  • Turn the gas fireplace completely off
  • Create a spark to start the pilot flame
  • Keep the pilot flame on
  • Start the main burner flames
  • Adjust the size and heat output of the main burner flames

In order for us to use these controls we need to push the dial in and turn it anticlockwise through the various positions.

We’ve covered how we use these controls to light and start a fire in our gas fireplace for more information.

These controls can vary significantly in terms of looks between types, brands and models of gas fireplace but all offer the same or very similar functionality.

For example, the controls for our old gas insert consist of buttons and levers.

Gas Fireplace Burner Assembly

The images below provide indications of what other gas fireplace controls can look like.

Example of another type of gas fireplace controls


The ignition system on a gas fireplace starts the flames.

One of the main parts of a gas fireplace that makes up a component of the ignition system is the pilot, with the other main components providing the spark to light this pilot flame.

The pilot light in a gas fireplace can be considered as a ‘starter flame’ that helps to ignite the main burner and therefore the main set of a flames.

The ignition system and pilot are typically hidden away somewhere around the top of the burner assembly, below the fireplace media and out of view from the user.

The ignition in our gas fireplace insert is located left of the controls and burner tray.

Gas Fireplace Ignition
The ignition in our gas fireplace

It would be hidden below the coals and the combustion matrix during a fire when these parts are replaced.

The ignition system inside a gas fireplace is often made up or two or three smaller components, which could include:

  • Pilot light
  • Spark electrode
  • Thermocouple
  • Thermopile

The actual parts that an ignition of a certain gas fireplace contains can depend on factors such as the type of gas fireplace, its age, and the make and model.

The ignition in our own gas fireplace, which is a relatively older model of fireplace, contains the following parts:

  • Pilot light
  • Spark electrode
  • Thermocouple
Gas Fireplace Parts Ignition Labelled
Gas Fireplace Ignition
Gas Fireplace Ignition Flame

Our gas fireplace uses a ‘double-action piezo spark’ ignition system, and an ignition in another model of gas fireplace may look slightly different and have a different arrangement compared to ours.

More modern versions of gas fireplace may have a thermopile instead of, or as well as, a thermocouple.

Gas Supply Pipe & Valve

Gas fireplaces use gas as the only source of fuel and so this gas must be supplied to a gas fireplace from elsewhere in the home via a dedicated gas supply pipe.

The supply pipe is also typically fitted with a shut-off valve that can be used to isolate the gas supply from the fireplace.

This supply pipe and shut-off valve is located around the side of the chimney breast in which our gas fireplace insert is installed.

Gas Fireplace & Gas Line
The pipe (left) supplying gas to our fireplace

As these photos were taken during summer when the fireplace was off and not in use, the gas supply is shown to be shut-off.

Gas Fireplace Main
The shut-off valve for this pipe

If the handle to the valve on a gas fireplace is shown perpendicular to the pipe then the gas supply is typically off. A valve handle that is turned parallel with the pipe typically indicates that the supply is open.

Many gas fireplaces valves can be found within the controls area of the fireplace itself, as indicated in the video below.

Firebox Liner

The firebox of a gas fireplace is often lined with fire-resistant panels.

As an example, our gas fireplace has ceramic panels on the back and sides of the firebox, referred to in our owner’s manual as the ‘rear ceramic tile’ and ‘rear taper pads’.

Gas Fireplace Vent Hood
The back panels on our gas fireplace

These panels may or may not be removable from different types and models of gas fireplace but for our version they are.

Gas Fireplace Side Panel
SIde panel
Gas Fireplace Brick Pad
Back panel
Gas Fireplace Panels Removed
Side and back panel removed


Most gas fireplaces will have some form of positive venting arrangements that allow waste air to safely leave a home.

This will be the case for natural (b-vent) and direct vent types of gas fireplaces, but ventless gas fireplaces don’t typically require any direct venting arrangements.

For natural vent gas fireplaces (like ours), there’s typically an opening within the top of the firebox that allows waste air to leave the home up the masonry chimney or flue.

Gas Fireplace Chimney
The open vent at the top of our gas fireplace

B-vent gas fireplaces take air from the room and so the front of our gas fireplace is open with no glass.

For direct vent gas fireplaces, both clean and waste air are vented externally.

You’ll therefore typically find air vents located out the back of direct vent gas fireplaces, and they’ll also typically have a glass front to the firebox to keep the air within the room and the fireplace separate.

Other Parts Of A Gas Fireplace

Hearth & Surround

The hearth is a platform of non-combustible material that many forms of fireplace, including gas fireplaces, sit on and/or protrude out the front and sides of the fireplace.

Our gas fireplace insert sits on a hearth and has a suitably sized hearth extension that sticks out the front and sides.

Gas Fireplace Hearth
The hearth for our gas fireplace
Gas Fireplace Surround
The surround

Not all gas fireplaces will require the use of hearth.

Hearths are typically required where the front of a gas fireplace is open, such as for many natural vent inserts, for safety purposes.

For gas fireplaces that have glass fronts, such as direct vent and ventless gas fireplaces, a hearth or hearth extension may or may not be required.

The requirements for a hearth usually come down to what is required by the manufacturer of a specific model of gas fireplace.

See our article on gas fireplace hearth requirements for more information specific to gas fireplace hearths or check out our complete guide to hearths for all types of fireplaces.

Oxygen Sensor

An oxygen sensor is another part that’s typically found in ventless forms of gas fireplaces only.

As ventless gas fireplaces don’t vent waste air externally, they must burn the fuel cleanly enough to produce an acceptably low level of by-products that are safe to put back into the room.

Any oxygen sensor is typically required inside ventless gas fireplaces to help ensure that oxygen levels within the room don’t go below a certain level, otherwise the gas fireplace may shut itself off for safety purposes.


Certain models of gas fireplace can have blower(s) built into them that help spread the heat more efficiently into the room from the fireplace.

Wall Switch

A wall switch may often be installed alongside more modern gas fireplaces that utilise electronic intermittent pilot ignition systems.

A gas fireplace can be turned on and off at the switch of one of these buttons.

Remote Control

Alongside wall switches, many modern gas fireplaces can also come with a remote control that allows you to use a gas fireplace from the comfort of your seat.

Cable Fixings

Certain gas fireplaces can have cables fixings on the back of the units to secure them to the back wall of the opening, such as at the back of a masonry fireplace for insert models.

An example of this can be seen with our old gas fireplace insert.

Gas Fireplace Insert Back
The cable fixings on the back of our old gas fireplace insert

Further Reading

How To Light A Gas Fireplace

Gas Fireplace Hearth Requirements

Gas Fireplace Efficiency Explained

Do Gas Fireplaces Need Electricity?

A Guide To Fireplace Surrounds

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