Although most contemporary furnaces have several safety mechanisms, heat exchangers can break over time. Because there is no barrier between the circulating air and the burner flame, a hole or crack in the exchanger may allow the burner flame to roll out the front of the furnace anytime the fan is turned on. This can start a fire quickly if there's anything flammable in the room.
Heat exchangers work by passing outside air through tubes filled with antifreeze (usually water) that conducts heat from the air into the antifreeze. As the antifreeze heats up it changes state from a liquid to a gas. This allows it to expand without breaking.
As antifreeze levels drop, so does the effectiveness of the heat exchanger. To ensure proper operation of your unit, you should check the level of antifreeze every year during the heating season. If the level is low, add more immediately. You can tell how much antifreeze is in your unit by looking for the color blue; if the level is below the glass, replace it.
If the heat exchanger starts to leak, turn off the power to the furnace immediately before checking for leaks. A hot heat exchanger will feel warm when touched by hand. If it feels warm when touched by foot, there is a leak. Also check the area surrounding the unit for signs of leakage or damage such as wet floors or walls.
By monitoring the flame, an experienced furnace technician can frequently discover heat exchanger difficulties. When the blower fan engages, the flame begins to leap and dance about, indicating that combustion air is escaping from the damaged heat exchanger. The technician may be able to detect this problem by listening for noise coming from outside the house or garage where it is located. If not, the heater will have to be replaced.
The furnace mechanic should be aware of any safety features in your particular model motor. Some units have a thermostat located inside the home office that shuts off the power to the unit if it gets too hot. This protects people from being injured by the heating system when they go into dangerous temperatures with the switch off. Other models have a timer which automatically turns off the power after a certain amount of time has passed. This prevents unnecessary use of electricity and saves money. Both types of controls should be checked by a professional technician before they are reinstalled in their original locations.
Heating systems work by using either gas or oil as a source of energy to produce heat. This is done inside the heat exchanger, which is a metal box connected to pipelines that carry gases or liquids through the heater. The two main components of a heat exchanger are the header and the tube sheet. The header is the connection point between the heat exchanger and the rest of the furnace.
What causes cracks in heat exchangers? Almost all premature heat exchanger cracks are caused by overheating. When a furnace lacks sufficient airflow, the heat exchanger overheats and experiences excessive stress from expansion and contraction. Heat stress generates cracks around weak places like as bends or welds over time. These cracks can lead to leaky units that waste energy and increase your heating bills.
If you plan to sell your house soon, consider having your HVAC system inspected by a professional company. They will be able to tell if there are any problems with the system's efficiency or function that may cause future damage. They can also give you advice on how to keep up maintenance on your unit. For example, they may suggest having the air filter changed every three months.
Cracks in heat exchangers can be difficult or impossible to detect when your furnace is running. However, if you have access to your boiler room or basement, then you should be able to see these cracks when the furnace is off. Cracked heat exchangers should never be used again; instead, replace them with new units.
Heated air flows across the surface of the heat exchanger, transferring its heat into the water flowing through it. As the water heats up, it expands, which pushes against the walls of the tank. This pressure washes away any dirt or debris that may have accumulated inside the tank wall.