Furnace | Heating and Air Conditioning
The Dangers of a Cracked Heat Exchanger
A gas furnace can provide a low cost and efficient form of heat for your home. In the southern states, a gas furnace may utilize natural gas or propane for fuel. Both are fossil fuels, and as a consequence produce carbon monoxide. A furnace depends upon the heat exchanger to safely exhaust it through a flue to the outside of the home. When the heat exchanger develops a crack or rust, deadly carbon monoxide leaks into the home resulting in illness, and is potentially life threatening to the home’s occupants. If the furnace shuts itself off, and/or a carbon monoxide detector alarms, contact your heating and air conditioning technician for service promptly.
Causes of a Cracked Heat Exchanger
When the furnace is unable to obtain an adequate airflow, the heat exchanger overheats, potentially cracking the heat exchanger. Not even a new furnace is immune to the potential for cracks if overheated.
One common cause of an overheated heat exchanger is a dirty air filter. A clogged air filter restricts the airflow through the furnace, causing it struggle for air and resulting in the overheating of the heat exchanger, resulting in dangerous stress fractures.
Follow the manufacturer’s recommendations for filter type and frequency of filter changes. Even filters that are typically changed every three months should be checked at least once per month. Numerous causes of increased dust, such as remodeling or windy and dusty conditions can increase the need for more frequent filter changes. Ideally, the filter should be checked every two weeks and changed if necessary.
Having a furnace or heating and air conditioning system installed that is correctly sized for your home and its individual characteristics is vitally important. Bigger is not better, and an over-sized furnace is an additional cause of overheating and heat exchanger cracks. The same is true of the home’s ductwork. Improperly sized ductwork will also affect the furnace or heating and air conditioning system’s performance, and can place too much strain on HVAC equipment when improperly sized for the home or the system.
Causes of Rust in a Heat Exchanger
Rust in a heat exchanger poses another potentially dangerous problem. This situation is also caused from having a furnace too large for the home. An over-sized furnace heats the home too quickly causing the furnace to shut off in a short period of time. This results in moisture remaining in the heat exchanger rusting it from the inside. This is a problem due to an additional byproduct of combustion – water. When a furnace first runs, the effect of the flame on the cold heat exchanger causes water vapor to condense inside of it. The increased frequency of on-off cycling of an over-sized furnace increases the expansion and contraction stress placed on the heat exchanger. This in turn, makes the heat exchanger more prone to stress fractures.
Signs of a Cracked Heat Exchanger
Quite often, the first signs of a cracked heat exchanger is no heat or an alert from a carbon monoxide detector. A cracked heat exchanger allows air from the furnace blower to affect the pilot causing it to flutter or even go out. This activates a safety switch, which shuts down the furnace.
A cracked heat exchanger cannot be repaired. When a crack or rust occurs, it must be replaced or a new furnace installed. If the furnace is over-sized, replacement will not prevent the long term problem, and replacement of the furnace or heating and air conditioning system will be the ideal solution.
All the problems and dangers due to an improperly sized heating and air conditioning system or furnace can be avoided by using an experienced, qualified and reputable heating contractor such as the professionals of Cypress Heating and Air Conditioning. Cypress’s certified HVAC technicians serve Katy, Plano and the surrounding areas.