This article will address some things that homeowners worry about in regards to their heat exchangers in their heaters and furnaces. The worry is that HVAC tech can fake a positive test. Home inspectors unfortunately cannot evaluate for this because they cannot physically disassemble the furnace. Individuals automatically assume that a cracked heat exchanger has the potential to increase carbon monoxides in the house and to pose a danger to those living in it.
Reality is that the heating contractor finds a cracked heat exchanger and says that the furnace needs to be replaced. Oftentimes they are not trying to pull a scam only if they are lying about finding a crack in the first place. If a company or individual believes that the heating equipment presents a danger to those in the house, they may disable, however this depends on company to company.
However if a heating company unscrupulously disables a furnace to strong-arm the sale of a new furnace, we have a problem.
Checking for Cracks in Heat Exchangers
There is no single check to find these cracks 100% of the time. The heat exchanger of a furnace separates the combustion from the air side, which keeps flue gases from mixing with supply air. In turn, it transfers the heat from the combustion of the fuel to the air blowing over the heat exchanger. Sometimes the tall tale way of knowing there are cracks is flame rollout. Flame rollout can be caused by many things however including sooting from incomplete combustion, inadequate combustion air that causes the flame to rollout or a crack in the heat exchanger tube, the gasket material breaking down and allowing pressure to leak into the exchanger or cell that allows higher positive blower pressure to enter the negative pressure heat exchanger.
A thorough visual inspection can be time-consuming and difficult. Some suggested techniques are wintergreen test, which sprays wintergreen oil into the combustion chamber to see if the smell is present. A smoke bomb test is another option where a smoke generator is placed into the heat exchanger then the outside of it is examined for smoking passing through the crack. These techniques however can make some fatal assumptions that can lead to damage later. For instance, a crack may be open when the heat exchanger is at or close to room temperature. In fact, some cracks only open when the unit itself is fired up and the equipment is hot.
Carbon Monoxide Detectors in The Home
The major question is will a carbon monoxide detector keep you safe from the poisonous gas. An alarm will not alert occupants in a home if there are levels in the home, but a detector will. It’s important to understand that these devices often have a limited life, some only five to seven years, so it’s important to replace them regularly for optimal safety for you and your family. Ultimately, they should be the last line of defense. Relying on these devices to keep you safe and ignoring a safety hazard is not smart. A cracked heat exchanger can lead to dangerous conditions in a home and costly repairs if left unfixed. If a professional suggests you replace your furnace and you’re uncertain, ask for a second opinion. Don’t simply ignore the professional advice.
It could be a hard lesson learned in the future.