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Sometimes red can be a good thing. But not on your furnace. If your furnaced is red-tagged, that means your HVAC technician or utility company found a critical safety issue that needs attention right away. Your technician is required by law to shut down the unit and place a tag on the equipment because of the potential danger it poses to you, your family, and sometimes even your neighbors. But before you panic, let’s take a closer look at the red-tagging process and what it means for you and your home.

Why are furnaces red-tagged?

Most furnaces burn natural gas or propane. Both forms of fuel are inexpensive and efficient for heating your home. However, if there are signs of a gas leak due to faulty piping or cracks in the heat exchanger, the technician will place a red tag on the unit and disable it until it is either repaired or replaced. The tag states the homeowner is aware of the risk and assumes responsibility if they turn the furnace back on before the issue is resolved.

The technician will place one of two types of tags on the furnace. The first is an A-tag, which is the most serious. In this case, the problem with the unit is critical and the equipment must be disabled immediately. A B-tag is not as serious and means you have more time before an HVAC professional or utility company shuts off the unit. Before turning the furnace back on, the homeowner will have to provide proof of repair or replacement.

What are the common problems?

There are a number of reasons why a furnace may be red-tagged. Here are a few common causes:

• Cracks in the heat exchanger
  The heat exchanger is a series of metal tubes that heat up when the furnace is on. Over time, the contrast between the tubes heating up and cooling off may result in cracks that allow flue gases, such as carbon monoxide, to be released into your home’s air supply. Carbon monoxide is a serious health hazard and can be lethal with prolonged or heavy exposure.

• Leaky or improperly installed flue
  The furnace exhaust pipe or flue helps vent harmful gases such as carbon monoxide out of your home. It usually runs from the combustion chamber and up to the attic where it is vented outdoors. Over time the flue can become loose or start to leak water or worse, gas. If you notice condensation build-up on or near your exhaust pipe, contact an HVAC professional right away as this could mean a carbon monoxide leak.

• Lack of Routine Maintenance
  Perhaps the most common issue that can cause a furnace to be red-tagged is the lack of routine maintenance. Like a car or any other major appliance, your furnace requires regular check-ups to keep it running efficiently year after year. Running a furnace with a dirty air filter can cause dust to build up over the heat exchanger, hastening metal fatigue and causing cracks over time. It’s important to change your furnace air filter at least every three months to keep your system operating at peak performance.

What are your options if your furnace is tagged?

If your heating and cooling professional determines the cause of the problem is a cracked heat exchanger, you may be able to replace it without having to purchase a new furnace. A good rule of thumb is that if your furnace is less than 10 years old, consider replacing the heat exchanger if it is still under warranty or if the repair cost is less than 25 percent of the total system replacement. Otherwise, it may be more cost-effective to purchase a new unit altogether.

If your furnace is red-tagged, it’s always a good idea to get a second (or third) opinion. You can ask your HVAC professional to point out specific issues, especially with the heat exchanger. If there’s only a hairline crack and the carbon monoxide levels are below 30 parts per million, it may still be safe to run your furnace, but it should still be monitored.

Family owned and operated since 1980, Heating and Cooling Two can help service all of your HVAC needs. Contact us today to schedule a repair or routine maintenance.