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September 06, 2023

Why Is My Furnace Not Working?

An HVAC technician inspecting all parts of a furnace for issues

As the chill of winter settles in, there’s nothing quite as unsettling for homeowners as a malfunctioning furnace. Unfortunately, furnace issues can be quite common. This is especially true for older models that might need replacement.

Whether you’re experiencing a sudden loss of heat, strange noises, or erratic performance, understanding the underlying issues and potential solutions is crucial to maintaining a comfortable and functional home. To help you better understand yours and what may be going wrong, we’re going to break down the different parts of a furnace and the common concerns we encounter with them.

So, if you’ve ever asked yourself, “Why is my furnace not working?” — you’re in the right place. Let’s equip you with the information you need to restore warmth to your home!

8 Parts of the Furnace Prone to Breaking

HVAC systems like the furnace consist of complex layers that may initially overwhelm you. Let’s simplify things by focusing our attention to common parts of a furnace that often require professional maintenance:

    1. Control Board

Furnace not working? Check the control board first as it regulates all components and connects all wiring from the power switch to the furnace.

Over time, the quality of a control board deteriorates due to thermal expansion, loose wiring, and power surges. These issues can leave you with a furnace that won’t turn on. You’ll likely see warning lights on the diagnostic system indicating which parts require repair.

    2. Blower Motor

The furnace blower motor controls the airflow in your heating and cooling system. It turns on the fan and assists in circulating air throughout your home.

Blower motor issues begin when dust accumulates quickly indoors, weakening the strength of the fan. You might even reach a point where this part turns on and off repeatedly, causing your furnace to not work properly. Usually, all it takes is a simple thermostat adjustment to restore things to normal, but more extensive repair may be required.

Gloved hands opening the case on a wall-mounted thermostat

    3. Thermostat

Parts of the furnace extend throughout the house! This one helps regulate temperature by telling the heating system to increase or decrease the level of warm air indoors.

Check your thermostat if you’re encountering furnace issues—you may just need to replace the batteries in the wall unit. However, if this doesn’t do the trick, you will likely need a furnace repair professional to check for faulty wirings and heat anticipator issues.

    4. Heat Exchanger

A heat exchanger is a metal shield between the combustion chamber and the blower that dispenses the heated air into your home.

DIY repairs are highly discouraged due to the risk of further complications. Instead, you should have a professional thoroughly inspect the tubes. They’ll also clean this component and its interior to remove soot build-up, returning the furnace to its working state.

    5. Ventilation System

Never underestimate the power of air filters in a gas furnace. These clean the air entering your home by removing dust, pollen, and pet hair.

A dirty air filter can be the reason your furnace is not working. The good news is that you can easily replace a furnace filter yourself! They’re sold at most hardware stores, and the replacement shouldn’t take long at all.

    6. Gas Valve

The gas valve controls the flow of gas to the pilot light and burners—you can probably already see why an issue with this is a serious problem.

HVAC professionals recommend staying on top of furnace preventive maintenance to keep the gas valve in check. Doing so prevents a gas leak, ensures proper heat is delivered indoors, and keeps your gas line free from blockages.

A furnace’s gas valve

    7. Pilot Light

As far as parts of the furnace go, this one could be the most important.

The furnace pilot light is used to ignite the natural gas released into the main burner. When its blue flame goes out, your furnace won’t start.

There are several reasons why this might happen: a generally dirty furnace, a loose thermocouple, a gas supply shortage, etc. If you’re unsure why yours has gone out, the best course of action is to call an HVAC technician immediately.

    8. Flame Sensor

This component ensures there’s always a burning flame running inside the furnace. If it detects the absence of fire, it will completely shut down the heating system to prevent carbon monoxide poisoning or worse, an explosion.

When a flame sensor has problems, the furnace will turn on but shut down abruptly. It’ll continue doing so until it detects a burning flame, rendering your furnace useless until you get it repaired by a professional.

Furnace Not Working? Call LG Home Comfort!

Furnace maintenance is complicated, so entrusting an HVAC professional is the best way to keep it running right. No matter the problem, we’ve got you—and all the parts of your furnace—covered all year round!

Whether it’s furnace repair, installation, or preventative maintenance, you can trust the experts at LG Home Comfort to provide long-term solutions. We’re the masters of all things HVAC and take pride in helping keep our client’s homes comfortable, safe, and warm.

Contact us today to get a quote.

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  • Once an initial service has been completed, the customer will be on a one-year commitment
  • After the initial 12 months, the contract will be renewed on a month-to-month cadence
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