If your gas fireplace keeps shutting off or won't stay lit, you're not alone — it's one of the most common service calls we receive across Northern Virginia. Before you panic, here are the five most likely culprits:
1. Faulty Thermocouple The thermocouple is a safety device that detects whether the pilot light is on. When it fails, it shuts off the gas supply as a precaution — even if the pilot is actually lit. This is the #1 cause of a fireplace that won't stay on.
2. Dirty Pilot Assembly Dust, debris, and soot can accumulate on the pilot assembly over time, weakening the flame. A weak pilot can't generate enough heat to keep the thermocouple engaged, causing the unit to shut down.
3. Drafts or Airflow Issues If your fireplace is near a window, exterior door, or in a drafty room, wind can blow out the pilot light. This is especially common in older homes in areas like Alexandria and Falls Church.
4. Gas Supply Problems Sometimes the issue isn't the fireplace at all — it's the gas supply. A partially closed valve, low gas pressure, or an issue with your main gas line can all prevent proper operation.
5. Worn-Out Igniter Electronic igniters can wear out over time and fail to produce enough spark to light the pilot. This is common in fireplaces that are 10+ years old.
What Should You Do? While some of these issues (like checking for drafts) are simple to identify, most require a trained technician to diagnose and repair safely. Gas fireplace work involves live gas lines — it's not a DIY project.
If your fireplace won't stay lit, give us a call. We offer same-week appointments across the DC Metro area and can usually diagnose the issue in a single visit.
