4 Gas Furnace Problems That Signal an Impending Heating Emergency

Furnaces may develop problems in the course of their usable life. However, the last thing anyone wants is for their furnace to break down during the cold season. Luckily, before breaking down, furnaces may exhibit some warning signs you should not ignore. Failure to troubleshoot and repair the appliance can cause the heating system to shut down, leading to a heating emergency. Therefore, as you operate your gas furnace, beware of the following problems that require immediate attention to avoid a heating emergency.

1. Ignition Problems

Gas furnaces use a pilot light to ignite the burners in the combustion chambers. The pilot light should remain on at all times. However, it can go off due to a strong draft, and in this case, you can simply relight the pilot. If your furnace's pilot light goes off even after relighting it, it could signal a problem with the thermocouple or flame sensor.

A flame sensor is a safety component that turns the gas off when the pilot light goes out. If the thermocouple didn't turn off the gas, all the gas released into the furnace would end up in your home. A faulty thermocouple can intermittently close the gas valve and cause the pilot light to go off. Reigniting the pilot light will only provide a temporary fix. If the flame sensor fails, the furnace will stop working. 

2. Strange Noises During Operation

Is your furnace producing strange banging, rattling, or popping noises during operation? These sounds could signal a problem with the blower motor. The blower motor is the component that turns on the blower fan and pushes warm air from the furnace and into the individual rooms. If the blower motor or its fan belt is worn or cracked, it will produce strange noises.

Some other problems that may arise from a faulty blower motor include overheated blowers, a burning smell around your furnace, poor airflow in the supply vents, and inadequate heating. Over time, a faulty blower motor or blower motor fan belt may malfunction. Consequently, the furnace won't be able to push warm air into the ductwork, which will lead to no heating. Therefore, don't ignore any unusual noises coming from your furnace. 

3. Funky Smells and Soot Buildup

Gas furnaces have a heat exchanger, which is the component that transfers heat from the heated gas to the air, all while preventing the gases from mixing with the air. However, the heat exchanger may crack or rust due to old age and poor maintenance. Cracks cause natural gas and exhaust gases, such as carbon monoxide (CO) to leak into the home.

When inhaled, carbon monoxide can cause a life-threatening condition known as carbon monoxide poisoning. Every year, at least 50,000 people visit the emergency room for CO poisoning in the U.S. Therefore, besides causing heating problems, a failing heat exchanger can also endanger a household. Look out for the following signs that indicate your heat exchanger may be leaking gases:

  • Soot buildup in your furnace
  • A funky sulfur smell in your home
  • A yellow or orange pilot light
  • Rattling or banging noises when the furnace is on

Replace the cracked heat exchanger to protect your household from CO poisoning. To prevent a safety hazard, turn off the furnace's gas supply and call a heating contractor for immediate repairs.

4. Rapid Cycling

Rapid cycling or short-cycling occurs when the furnace turns on and off without completing a heating cycle. The following furnace problems can cause your system to shut on and off at random intervals:

  • Dirty ductwork or air filters
  • Blocked supply or return vents
  • Damaged or dirty flame sensor

The problem with short cycling is that it overworks the furnace. Therefore, the system constantly overheats and turns on and off to prevent damage to the components. Over time, the flame sensor, blower motor, and other key components may fail. When this occurs, the furnace will stop working altogether. Therefore, address this issue to prevent costly component repairs.

Is your furnace exhibiting the above problems? If so, you may soon encounter a heating emergency. Contact a local contractor who can handle heating repairs.