Like most homeowners, you probably already know a few of the basics concerning furnace maintenance such as how changing your furnace filter can help keep the system from malfunctioning. However, there are many things that can go wrong with a household furnace during the course of the winter, and most of them are a complete mystery to the average homeowner. Here are three major causes of furnace malfunctions:

Shorts in Thermostat Wiring

Fortunately, this is among the easiest and least expensive of furnace problems for HVAC professionals to fix. If thermostat wiring has shorted out, has worn out,  or has come lose, the furnace won't come on when the heat is turned up, but there's nothing wrong with the more important, expensive parts of the furnace. A skilled HVAC technician can replace a thermostat fuse in under five minutes after they detect a short by using a tool, called a multimeter, that is designed to measure electrical currents and voltage.

Dirty Flame Sensors

Flame sensors rust over time due to the minuscule amount of water produced by the flames burning fuels. Rusty, or dirty flame sensors are one of the main causes of a furnace failing to start when the heat is turned on. Most of the time, a quick cleaning of the flame sensor is all that it takes to get the furnace up and running again, and if the rust is too extensive, the flame sensor can be replaced fairly quickly.

Blower Motor Failure

Unlike the preceding situations, a blower motor failure is likely to be a serious problem that won't be able to be fixed within a short period of time. Reasons for blower motor malfunction include:

  • Electrical shorts in the windings
  • Dirt and grime in the bearings

Dirt, dust, and other debris can build up in the bearings if you fail to use a furnace filter, if the one that you are using is substandard, or if the filter has not been changed as often as it should have been.

Faulty Controls

Secondary internal controls such as circuit boards or those used for time delay features can frequently wear out, and this can cause your furnace not to start. Having these replaced will fix the problem.

Although most furnace malfunctions can be circumvented by scheduling regular maintenance visits from a heating repair professional, there are cases where the furnace is simply too old and worn out for it to make sense to baby it along. If you suspect that your furnace may fall into that category, you'll be glad to know that tax write offs are available for those who have new home furnaces installed!