Tuckers Air Conditioning, Heating & Plumbing Blog

Safety Features in Gas Furnaces

The modern gas furnace has improved in safety by immense leaps over the models of fifty years ago. Although natural gas-powered furnaces still have a reputation as potential safety hazards, this is largely a myth: with proper annual maintenance and attention to repair needs, a gas furnace is no more dangerous than any other heating system you can have installed in your home.

A number of features help keep your home’s furnace safe. We’ll look at a few of these safety devices. To keep them in good shape with repairs and maintenance, call Tuckers Air Conditioning, Heating & Plumbing. We can assist you with all your requirements for heating in Rockville, MD.

Some gas furnace safety features:

  • Furnace fan limit switch: This device prevents the furnace from overheating. It’s located just below the plenum and measures the heat on the metal. When the temperature of the plenum rises too high, the limit switch shuts off the burner. To further regulate the furnace, the switch turns off the blower once the temperature drops down to a set level. Finally, when the furnace drops to the lowest setting on the switch, the switch turns the blower back on. The manipulation of the blower is important to how the furnace regulates the temperature after turning off the gas.
  • Thermocouple: This is a simple component made of two strips of different metals coupled at one end. Because of the thermoelectric principle called the Seebeck effect, electric voltage runs through the two pieces of metal when in the presence of heat. The higher the heat, the higher the voltage. The thermocouple is placed where it can measure that the pilot light is burning. Should the pilot light go out, the thermocouple’s loss of voltage will shut off the gas valve, preventing unburned gas from flooding into the combustion chamber and creating an explosion hazard.
  • Mercury sensor: These devices are replacing thermocouples as the way of detecting if the pilot light is on. When the pilot light produces enough heat, the rise in mercury in the sensor keeps the gas valve open. It closes when the mercury drops far enough. Mercury sensors have longer service lives than thermocouples, one of the reasons they have gained popularity.

Keeping your furnace well-maintained with professional inspections once a year (usually before winter starts) is the best way to keep your system safe. Your technician will make sure all your safety devices are operating, and will check to see that no other dangers, like cracked heat exchangers, are developing.

Call Tuckers Air Conditioning, Heating & Plumbing to sign up for maintenance for your heating in Rockville, MD. We have the trained staff to handle any problems you may have.