How to Turn on a Gas Fireplace With a Wall Key

Gas Fireplace

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Project Overview
  • Working Time: 1 - 2 mins
  • Total Time: 4 - 5 mins
  • Skill Level: Beginner
  • Estimated Cost: $5 to $10

For the perfect combination of comfort, low maintenance, and ease of operation, gas fireplaces can't be beat. Gas is clean, and it burns warm. Plus, you never need to clean up ashes later on. 

While some gas fireplaces ignite with the flip of a wall switch, other fireplaces are lit by turning a wall key while applying flame from a lighter or long match. Operation is fast, easy, and safe—as long as you follow the lighting procedure in the correct manner.

Where to Find the Gas Valve Knob

The gas valve knob is the junction between the main gas pipe and the gas fireplace. When closed, the gas valve knob acts as a gate to prevent gas from flowing to the fireplace. When opened, gas will flow. The valve can be opened partially or in full.

The gas valve knob usually has a round metal flange with a square or hex hole in the center. It will be located:

  • On the wall on either side of the fireplace, usually about a foot off the floor; or
  • Ground-level on the fireplace apron; or
  • Ground-level on the flooring around the fireplace


Usually, the gas valve will be no more than an arm-stretch away from the fireplace. The valve must be within this distance to allow the user to turn on the gas and ignite the fireplace at the same time.

Safety Considerations

Flammable and potentially dangerous, natural gas is colorless and odorless. To help with detection, gas companies treat natural gas with trace amounts of mercaptan, a pungent odor similar to rotten eggs or sulfur. 

If you smell significant natural gas build-up in the home, turn off the gas to the fireplace, open all windows and exterior doors, and leave the house until the smell is gone.

When turning, do not force the key. This may break the gas valve knob or the key.

Troubleshooting Turning on a Gas Fireplace With a Wall Key

Cannot Find the Pilot Light

Wall key gas fireplaces do not have pilot lights. Manually lighting the fireplace substitutes for the pilot light. Gas fireplaces that operate with wall switches do have standing pilot lights, though.

Gas Flows but Won't Light

Turning the wall key alone will not light the gas fireplace. You do need to apply a flame to flowing gas to light the fireplace. If the gas is flowing, the problem may be with the flame. Turn up the flame on the kitchen lighter or use a new lighter.

Wall Key Is Lost

It can be easy to misplace the fireplace wall key since it should never be left in the gas valve knob. Look on the fireplace mantel, on the fireplace apron, or in a nearby shelf or cabinet. It's also helpful to look in the kitchen if you have a drawer with general items. If you still can't find the key, buy a new one for $5 to $7 at your local home center or hardware store.


Never turn on a gas fireplace valve with any makeshift tool. You risk not being able to turn off the gas quickly in the event of an emergency. Only use the wall key designed for the gas valve.

What You'll Need

Equipment / Tools

  • Gas fireplace key
  • Kitchen lighter (if not using long matches)


  1. Locate Gas Valve Knob

    Find the gas valve knob on the wall or floor. Place the key nearby. Do not place the key in the valve yet.

  2. Open Front of Fireplace

    Open up the glass doors or screen to the fireplace.

  3. Locate Ignition Area

    On or around the log insert will be a pipe with holes or valves. This is where you will light the fireplace.

  4. Prepare Ignition Source

    Ready the kitchen lighter or long matches. Do not light them yet.

  5. Place Key in Gas Valve

    Insert the wall key in the gas valve. Make sure that the key fully seats in the valve. Do not turn yet.

  6. Light Ignition Source

    Turn on the lighter or strike the match. Hold the flame about 1/2 inch above the ignition area.

  7. Slightly Turn on Gas Valve

    Rotate the wall key a quarter or half turn counter-clockwise. Do not turn it on all the way yet. The flame should light.

  8. Turn Gas Valve on Full

    Continue slowly turning the valve counter-clockwise until the valve stops. If you decide to have a lower flame, stop short of this. Be careful not to turn it down too low, or you risk extinguishing the flame with gas still flowing.

  9. Remove Wall Key

    For safety, remove the wall key. Wall keys left in valves can break off, or they can be accidentally turned.

  10. Turn off the Gas Fireplace

    To turn off the gas fireplace, replace the wall key. Turn the wall key clockwise until it comes to a firm stop. The flame will taper down and extinguish on its own.

When to Call a Professional

Call a licensed plumber for any issues relating to the gas line within the house. Not all plumbers are equipped to work with gas lines, so check with them in advance. If you smell a gas leak outside of the house, call the gas company immediately.