Common Signs Your Furnace Needs Repair

Regular Maintenance Can Help Limit Issues that Cause Furnace Breakdowns

When the temperatures plummet and winter sets in, the last thing you want to face is an issue with your furnace. If you notice any unusual signs from your furnace – such as inefficient heating or loud noises – acting quickly can mean the difference between a minor repair and a costly system breakdown.

HVAC.com discusses some of the most common furnace repairs you may face this winter, how to fix them, and when to call a professional. We’ll also touch on maintenance tips to help keep you home warm and comfy.

Common Furnace Repairs

Some of the most common furnace repairs you may encounter this winter include:

Clogged Air Filters

A dirty and clogged HVAC filter can lead to a host of issues. Clogged filters reduce the air intake into your system, which can cause it to strain, leading to inefficient operation and high energy costs. In some cases, a dirty air filter can cause the system to shut down completely to avoid overheating.

Solution: Fortunately, a clogged filter is an easy fix. Check the condition of your filters monthly, and replace or clean them regularly, ideally every 1-3 months, to maintain optimal airflow and reduce your utility bills.

Thermostat Issues

In some cases, the thermostat – not the furnace – might be causing your heating-related issues. Dirty sensors and loose wiring can lead to a malfunctioning thermostat. The unit might also have dead batteries or was incorrectly set.

Solution: First, ensure that the thermostat is set to HEAT. You can adjust the temperature up a couple of notches and wait for the furnace to start up. If the thermostat has a blank screen or isn’t responding to any adjustments, replace the batteries. If this isn’t the issue, you can use a screwdriver to remove the thermostat cover and tighten any loose wiring. If you’re uncomfortable performing this task, contact an HVAC technician. They can either repair the thermostat or recommend a replacement.

Loud Noises

Aside from the gentle hum of your furnace running a cycle, they are relatively quiet. So, any unusual noises such as banging or rattling should raise a red flag. These furnace noises can indicate a mechanical issue or a broken or loose part.

Solution: Find the source of the noise and contact an HVAC technician to diagnose and repair it. The quicker the source of the noise is repaired, the less damage it will cause, potentially averting a complete breakdown or an expensive repair.

Failing Starting Mechanism

Every furnace initiates the heating cycle through a starting mechanism. Older models rely on a pilot light, while newer ones use electrical ignitions. If your furnace isn’t heating properly, a malfunctioning ignition or pilot light might be the culprit.

Solution: Contact an HVAC dealer to replace the starting mechanism. Since most furnaces stopped using pilot lights in 2010, you may want to consider replacing the entire system if the pilot light is bad, especially if it’s old and inefficient.

Blower Motor Issues

Your furnace’s blower motor plays a critical role in the heating process. It starts the blower fan that pushes conditioned air through the duct system and into your home’s living areas. You can tell if your furnace blower motor is bad if you notice unusual noises, a lack of airflow, or if the blower fails to turn on altogether.

Solution: If the blower motor isn’t running, check for a tripped circuit breaker or a blown fuse. If those are fine, the motor may need to be inspected or replaced by a technician.

Short Cycling

Furnace short cycling occurs when the system frequently turns on and off in short intervals, preventing it from effectively warming your home. This issue is often caused by a malfunctioning thermostat, clogged air filters, or an oversized furnace.

Solution: Start by checking and replacing the air filter if necessary to ensure proper airflow. If the problem persists, contact an HVAC technician for a thorough inspection. If your furnace is oversized for your home, it may need to be replaced with an appropriately sized unit.

Cracked Heat Exchanger

A cracked heat exchanger isn’t something to take lightly; it’s a serious issue that can cause carbon monoxide leaks, posing a significant safety risk to your home and family. Signs of a cracked heat exchanger include unusual smells, soot in and around the furnace’s burners, and a pilot light that is orange or yellow instead of its normal blue color. Installing CO detectors around your home can help detect the presence of carbon monoxide.

Solution: If you suspect a heat exchanger crack, it’s crucial to turn off your furnace and contact a qualified HVAC technician immediately for inspection and replacement.

Blower Belt Issues

A blower belt connects the furnace motor to the blower fan, allowing it to circulate air throughout your home. When the belt frays or malfunctions, it can lead to reduced airflow, a squealing or screeching noise, or complete blower failure.

Solution: Have a technician replace the damaged belt.

Bad Limit Switch

A furnace limit switch regulates the temperature inside the furnace and prevents overheating by shutting off the system when it reaches a preset limit. Signs of a faulty limit switch include frequent furnace shut-offs, inconsistent heating, or a blower fan that constantly runs.

Solution: If you suspect a malfunctioning limit switch, it’s best to have a professional HVAC technician inspect and replace it if necessary.

The Importance of Regular Furnace Maintenance

The best way to avoid the headaches that come with furnace repair and breakdowns is by scheduling regular maintenance for your unit. This service is performed by a professional HVAC technician, typically in the fall before you start using your furnace regularly.

During furnace maintenance, a technician typically inspects, cleans, and tests the system to ensure optimal performance and safety. This process often includes checking the burner, replacing air filters, and verifying that all components are functioning correctly to prevent breakdowns and improve efficiency.