{"id":478,"date":"2024-02-05T11:00:00","date_gmt":"2024-02-05T19:00:00","guid":{"rendered":"https:\/\/www.cozyheatinginc.com\/blog\/?p=478"},"modified":"2026-03-27T08:44:52","modified_gmt":"2026-03-27T15:44:52","slug":"help-my-furnace-wont-start-up-or-stay-on","status":"publish","type":"post","link":"https:\/\/www.cozyheatinginc.com\/blog\/heating-service\/help-my-furnace-wont-start-up-or-stay-on\/","title":{"rendered":"Help! My Furnace Won’t Start Up or Stay On"},"content":{"rendered":"
\n
\"cold-couple-sitting-on-couch-in-heavy-parkas-with-hoods\"<\/a><\/figure><\/div>\n\n\n

We\u2019ve experienced some intense winter weather already this year. With recent snowstorms and freezing-cold temperatures, it\u2019s a good reminder of how essential your furnace is to keeping you not only comfortable in your home, but safe as well.<\/p>\n\n\n\n

Unfortunately, it\u2019s when temperatures are at their coldest that a furnace can suffer a catastrophic breakdown, leaving you without heat. Let\u2019s go over what could cause a furnace to not start up and not stay on. If you find yourself without heat during a cold spell, be sure to call us for prompt heating repairs in Bothell, WA,<\/a> as soon as you realize there\u2019s a problem. We\u2019ll restore your heating as quickly as possible.<\/p>\n\n\n\n\n\n\n\n

Faulty Furnace Capacitors That Prevent Startup<\/strong><\/h2>\n\n\n\n

Your furnace requires many components to work properly. Two important ones are the electronic capacitors, the start capacitor and the run capacitor. They are tasked with the important job of controlling the blower fans. <\/p>\n\n\n\n

If either one of these capacitors fails, then your furnace could not possibly start or run. But the capacitors are not the only cause of furnace malfunction. Let\u2019s go over what else could be going on.<\/p>\n\n\n\n

How to Troubleshoot Furnace Startup Problems Step-by-Step<\/strong><\/h2>\n\n\n\n

There are several reasons your furnace may not turn on including:<\/p>\n\n\n\n

  • A miscalibrated or faulty thermostat. <\/strong>Even the tiniest malfunction with a thermostat could result in a misreading of the temperature in your house which will prevent the unit from signaling your furnace to turn on. Frayed wiring could also impact the thermostat and disrupt the signal it\u2019s trying to send to your heating system.<\/li>
  • An old electronic igniter.<\/strong> If your furnace is gas-powered, it still requires electricity to run. The system uses an electronic igniter which activates the burners. The igniter typically needs replacement every few years and can burn out before a routine maintenance appointment.<\/li>
  • A dirty or rusted-out burner.<\/strong> In a furnace, the burner is where the gas jets ignite to provide heat. However, if the burner has a buildup of dirt or grime due to a lack of maintenance, or if rust flakes get inside of it, it will experience problems drawing in enough oxygen to light the furnace.<\/li><\/ul>\n\n\n\n

    Why Your Furnace Starts Then Shuts Off Quickly<\/strong><\/h2>\n\n\n\n

    Again, this could be a thermostat issue. If the thermostat thinks it has reached the desired temperature, it will shut the furnace off. Other reasons this might happen include:<\/p>\n\n\n\n

    • A blown-out pilot light. <\/strong>The pilot light is the continuously burning flame that\u2019s used to light the burner and start a furnace. If it goes out for any reason after it\u2019s started up, then it\u2019s not going to cycle back on later.<\/li>
    • A faulty gas valve.<\/strong> This component controls how much gas flows into a furnace. If there\u2019s a problem with it, then the furnace won\u2019t like it because it won\u2019t have fuel to burn. If your pilot light is still lit but the furnace won\u2019t stay on, then this could be the reason.<\/li><\/ul>\n\n\n\n

      Frequently Asked Questions<\/strong><\/h2>\n\n\n\n