To repair a fireplace insert, turn off the gas and electricity, determine the problem, fill in the crack or hole, clean the unit, and then attempt to relight the pilot light. If necessary, replace the thermocouple before using the fireplace.
It is very important to turn off the gas and electricity before working on a fireplace. Since there are so many things that can go on with a fireplace insert, it is important to attempt to find out what the issue might be. A common issue is a crack or hole in the insert. If this is the issue, it is usually easy to fix.
If the crack or hole is visible and in a brick area, use retort cement to fill the area, but allow it to dry for several hours before turning the fireplace back on. If the hole or crack is in the metal area, only welding can repair it, so this may require a professional. After any repair, it is important to thoroughly clean the unit before lighting the fireplace again, as debris may cause a fire hazard.
Relight the pilot light and turn the gas and electricity back on. Test the fireplace for function, and if it does not work, replace the thermocouple by screwing in a new one. At that point, relight the pilot light and check for function, again.