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Why Was My Furnace Red Tagged?

Red-tagging is when a heating and air conditioner technician shuts down your furnace, deeming it inoperable. Mainly, there are two types of red tags. Type A red tag implies that the gas supply will be shut off immediately since your furnace poses an imminent threat to your safety. Type B red tag gives a warning of about 30 to 40 days to have the problem fixed.

A furnace receives a red tag from a technician or a utility company because it is unsafe to operate. The cracked heat exchanger, blocked flue vents, and patchwork duct system may increase toxic and dangerous carbon monoxide levels. The urgency to fix the furnace is essential and has to be taken seriously to avoid casualties.

Attic Furnace Install and Maintenance

Why Was Your Furnace Red-Tagged?

In most cases, the heat exchanger is usually the problem. The heat exchanger is a component in your furnace responsible for transferring heat from fuel combustion to the air circulating through your house. A cracked heat exchanger might allow carbon monoxide to leak from outside and into the air in your home. Carbon monoxide gas leak is a significant threat since it is odorless and hard to detect, which leads to death if exposed to it for long periods.

Other issues will also cause your furnace to be red-flagged such as the burner tube or gas valve having problems that may cause a gas leak that may lead to a fire hazard. An explosion may occur, causing it to be an unsafe condition for people in and around your home.

What to do When Your Furnace is Red-Tagged

The big question is, what do you do in such instances? It would be best to ask for a second opinion to get another set of eyes on the situation. Some companies have cameras installed with technology, allowing you to see what is going on as the technician is working while pointing out the flaw in the furnace.

If there is a crack, it will have to be exchanged no matter how small because the aperture cannot be sealed and will always be there. You may be required to replace the exchanger for half the price instead of buying a new furnace. Checking to see if the exchanger is still under warranty can buy you some time before purchasing a new furnace. Most warranties might extend for up to 20 years, which is enough to rethink purchasing a new furnace.

It is advisable to hire a well-licensed contractor with a good reputation. Service techs often find equipment so dangerous that they feel it is their duty and obligation to red-tag the furnace and shut it down, especially if it poses an immediate danger to life or property.

Your HVAC contractor will be the one to give you advice on whether to repair the furnace or purchase a new one. Sometimes the repairs may end up being way too expensive compared to buying a new one, especially if it is an old furnace that may operate at its lowest capacity causing many parts to fall apart altogether.

How to Prevent Being Red-Tagged

Furnaces require regular check-ups to ensure it is running efficiently and safely to prevent unnecessary hazards and costs. Make sure you are up to date with your maintenance services regularly. The furnace also requires proper care, for instance, cleaning the vents and replacing air filters every month—especially those that are dusty. The best way would be to clean a water filter with warm water and a cloth.

Adding a carbon monoxide detector can go a long way in notifying you of any leaks. Avoid relocating the furnace and knocking it while renovating to prevent minor damages that might cause issues after some time.

Even though red-tagging causes inconveniences, it is essential in improving and ensuring the safety of our homes. Waiting till winter to sort out the problem could leave you with no heat. Always seek a second opinion from an HVAC technician before purchasing or repairing your furnace.

It is always best to go with a little more capacity than recommended in the case of expansion tanks because it will not hurt your plumbing. If you are unfamiliar with the process, hiring a professional is always the best way to go. Plumbing services will help you decide on the best brand and size for expansion tanks and even cover maintenance duties.

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Customer Reviews

Called Absolute for my 81 year old landlord in the height of Summer heat. Scott came out to inspect the old beast of an AC and found many issues. He took the time to educate us, note everything, photograph it and provide several recommendations...and my stubborn landlord has done nothing LOL. A couple months later we asked that Scott come back out and he was there that same day.

Emily H.

Santa Ana, CA

I contacted Absolute Airflow to check my mother's AC, as it was not getting cold. The tech (Scott) arrived earlier than his scheduled time, and was very knowledgeable, professional, and most of very personable with my mother in letting her know that the issue was. Superb customer service Scott and thank you Absolute Airflow! I highly recommend Absolute Airflow.

Billy A.

Billy A.

Bellflower, CA

I have called in Absokite Airflow for my tankless water heater and A/C unit for maintenance. They were professional and took the safety precautions necessary including wearing a mask and cornering their shoes when entering my home. I recommend them highly. Shout out to Zack who took care of the tankless water heater.  They were professional and friendly.

Beatriz S.


Santa Fe Springs, CA

Carlos came to our house to access the A/C project and to give us an estimate. He was very knowledgeable and took his time to explain all the opinions in detail as well as the installation process and warranties. Tanner and Chris were the installers, they were very professional taking their time and attention to details. To keep our house clean while installing the new A/C system.

Robert M.

Robert M.

Whittier, CA