Old-fashioned conventional furnaces were simple in design. They were composed of a gas valve, pilot, burner, blower and venting. The thermostat connected directly to the gas valve, and the only safety was the pilot. Today, furnaces have many additional safety features, and while standing pilots are still available, most have been replaced with hot surface ignitors. Modern furnaces are equipped with circuit boards to organize and control the sequence of operations, and the circuit boards can burn out.
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Causes of Damage
A circuit board can easily incur damage from a number of sources. Condensation or water dripping onto the unit can cause the board to burn out. Other damage causes include electrical shorts from dust buildup and an individual touching the board improperly during cleaning. Excessive or prolonged heat can cause the board to burn out faster than otherwise.
Repair or Replacement
While it is possible for some specialty electrical technicians to fix a section of a circuit board, the cost is usually prohibitive. Generally, once a furnace circuit board burns out, the whole board must be replaced. Homeowners can follow the manufacturer’s wire diagram to replace the board, however, warranties can become void if someone other than a licensed heating, ventilation and air conditioning (HVAC) technician performs the work.
Regular cleaning and inspection is the best way to prolong the life of the circuit board and heating system as a whole. Cleaning keeps dust and dirt from a dirty filter off the board. Inspecting the entire heating system can reveal areas of potential concern, such as condensation or rust.