Why is My Central Heat Not Working?

Do you know how to troubleshoot central heating issues? Learn how to handle the most common causes, DIY solutions, and when an HVAC pro is required.

Cold Couple in Kitchen

Central heating systems heat homes by using a primary heating appliance, usually either a boiler or furnace. In homes equipped with a boiler, heat is delivered to the rest of the home using hot water or steam transported through pipes to radiators. In homes equipped with a furnace, commonly known as a forced air furnace, the home is heated by warmed air that is circulated through air ducts throughout the home. Regardless of whether the heat source is a boiler or furnace, the central heating system is part of your home’s heating, ventilation, and air conditioning (HVAC) system.

In this article, we will focus on central heating systems that rely upon a forced air furnace. Read on to learn how central heating works.

How Furnaces Work

Furnaces generate heat by burning fuel — usually natural gas, propane, or oil. (Some forced air systems run on electricity.) As the fuel is combusted, the heat produced in the burner passes through a heat exchanger. Next, air from the home's ductwork is blown over the heat exchanger, warming the air. The furnace's blower then forces the heated air back into the supply ductwork, distributing it throughout the home.

Central Heating Problems

Are you having forced air heating problems, or is your central heat not working? Central heating problems can be a major inconvenience. Once you understand the most common issues affecting central heating systems, you'll be able to troubleshoot them yourself and know what you can fix and what’s best left to the experts.

If your central heat is not working, it could be due to any number of factors.

Problem: Heater is blowing cold air

Check your thermostat and make sure it’s set to the correct temperature. Otherwise, the thermostat may be experiencing one of the following issues.

  • Dirty air filter. Change your air filter, also known as a furnace filter, and see if that fixes the problem.
  • Leaky ductwork. Check for leaks in the attic, and seal off any leaks and insulate your ducts accordingly.
  • Pilot light issues. Make sure your furnace's pilot light is lit. If it won’t light, make sure gas is flowing to it. Check the gas valve and verify that it’s turned on. If your gas valve is on and your pilot light still won’t light, consult an HVAC repair professional.
  • Lack of fuel. Check to make sure your furnace is getting the fuel it needs to run properly.

If none of these DIY fixes corrects the problem, contact an HVAC professional and have them examine your heating system more thoroughly.

Problem: Heater won’t shut off

Make sure your thermostat is set to “auto” instead of “on.” Otherwise, your problem could be one of two issues.

  • Your thermostat is broken or not wired properly.
  • Your furnace blower is malfunctioning.

First, examine your thermostat’s wires to ensure everything is plugged in correctly. Next, reset your thermostat to factory settings and try running your system again. If this doesn’t resolve the issue, you may need to replace your thermostat. If you replace your thermostat and your furnace continues to run, your problem could be a blower issue. This is a problem that should be handled by an HVAC professional immediately.

Problem: Certain parts of the house are not receiving heat

If your heater isn’t distributing heat evenly throughout your home, the problem is likely one of two things: dirty air filters or inadequate ductwork. Check your air filters and change them if needed. If the filters are clean or if replacing them doesn’t do the trick, you may need to inspect your ducts for leaks. If the issue points to a problem with your ducts, contact an HVAC professional to inspect your ductwork.

As with any of your home's major systems, preventive maintenance is key to ensuring the smooth and efficient functioning of your central heating. Hire a trusted HVAC service technician to inspect and maintain your furnace every year before cold weather settles in. A professional can address problems that might cause breakdowns or expensive repairs during busy winter months.

When it comes time to replace your heating system or to make the most of your current one, an American Home Shield® Heating Home Warranty is a great way to protect your investment. Our flexible plans can help you protect your home as well as your household budget. 

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