How to Repair a Natural Gas Fireplace Insert

What You'll Need
Retort cement
Long match or lighter
Compressed air
New thermocouple

Installing a natural gas fireplace insert can improve the look of an existing fireplace and maximize its efficiency at the same time. Yet, from time to time, problems may develop within the insert itself. In order to diagnose and fix these problems, try following the steps below.

Step 1 – Turn off the Gas and Electricity

Always turn off the gas when working on a natural gas fireplace to reduce the chance of an explosion. Because these fireplaces are operated by switch, it may be wise to turn off the electricity as well to reduce the chance of getting shocked while working on the unit.

Step 2 – Determine the Problem

There are many things that can go wrong with a natural gas insert, but the two most common problems are cracks or holes developing in the firebox around the insert and the fire not starting when the switch is activated. If a hole or crack is visible in the firebox wall, continue reading step 3. If the fire won’t start skip down to step 4.

Step 3 – Fill the Crack or Holes

If the firebox around the insert is made of masonry material or brick, the fix is relatively easy. Simply trowel retort cement over the damaged area. Retort cement is a furnace cement that is rated for extremely high temperatures. Once the cement has been properly applied to the affected areas, let it set for a few hours before turning the flame back on. Turning the flame on will expedite the drying process of the cement, but drying it too rapidly or too soon may cause the cement to crack. If the firebox around the insert is metal, it may be slightly difficult to repair. Any cracks in the metal will need to be welded shut. A skilled do-it-yourselfer will be able to use a welder to do the job, but it may be wise to call a professional welder if one is not comfortable attempting this fix.

Step 4 – Clean the Unit

If the insert will simply not light, there are a few different things that could be wrong. First, try cleaning the insert. Occasionally dust or debris may collect inside the fireplace and plug the area from which the gas is released inside the insert. Clean this area thoroughly to ensure no plugs exist.

Step 5 – Try Relighting the Pilot Light

If the pilot light has gone out, the fireplace will not be able to start up. Furthermore, turning off the gas to the insert before working on it, as a safety precaution, will have ensured that the pilot light is gone. So, to relight it, turn the gas and electricity back on and examine the gas valve located in the back of the fireplace. Make sure the valve is set to pilot. Carefully, light the pilot light with a long match or lighter. Test the fire place. If the flame still does not sprout up, turn the gas back off before continuing any work on it.

Step 6 – Replace the Thermocouple

Locate the thermocouple mounted on the pilot assembly. Most thermocouples can be unscrewed by hand and are easy to find a replacement for. The most important detail is the size of the thermocouple, because the replacement must be the exact same size as the original in order for it to work properly. Just screw the new thermocouple into place, relight the pilot light and test the fireplace insert.