Take an Unsafe Furnace Seriously

3 pros!
If your heating system’s red tagged, or labeled unsafe, pay attention.
Having your furnace “red tagged” means an HVAC professional or a utility worker has deemed it so unsafe that the natural gas is shut off until the problem is fixed or the unit replaced. While a heating system isn’t always actually tagged, the danger is the same.
Getting to the root of the problem
Several problems can lead to a heating system being deemed inoperable due to safety concerns. Carbon monoxide (CO) concerns can relate to:
A cracked heat exchanger: The heat exchanger separates heat energy from combustible fuel, letting only heat into the home. When it cracks, CO and other hazardous combustion gases seep through the crack and, instead of being vented outside, work their way through the ducts into living spaces.
Blockages in the chimney: These can redirect CO.
Cracked venting systems: These compromise what should be a sealed system that safely sends CO outside.
Electrical hazards: Water or flooding can cause these, as can other system damage. That can let CO access components of the heater it shouldn't and eventually get into living areas.
Various problems: Gas pressure, dirt buildup on the furnace's burners or the lack of enough air for the combustion process can produce difficulties.
No matter what causes the problem, homeowners should take the situation seriously.
A second opinion
Get a second opinion to be safe and avoid paying for unnecessary work.
Work with a reputable HVAC expert to determine the best course of action. Consider the components that need to be repaired and the cost for materials and labor.
A new exchanger?
Without warranty coverage, replacing a cracked exchanger is generally costly because this component is difficult to access, and a service professional must dismantle the system to replace the part.
That means it may be more cost-effective to upgrade the heating system instead of replacing the exchanger.
A new furnace?
Often, homeowners replace the furnace if the exchanger is cracked and the system’s out of warranty. Check your warranty before deciding. A full replacement can sometimes be the only way to address a red tagged system.
In many cases, homeowners opt to upgrade systems to get safe HVAC equipment that operates more efficiently, will help them save on energy bills and employs a sealed combustion system to enhance home safety.
Keeping things safe
If you'd like to avoid a red-tagged furnace, make a commitment to have your heater serviced every year. With careful attention to HVAC maintenance, you can be sure the system is cared for and the heat exchanger — and all other components — will stay in the best shape possible. If a problem develops, you'll know about it right away.