When your heating system fails you naturally assume the furnace is the problem. But the solution may actually lie in knowing how to troubleshoot a thermostat.
Why? Because many times the thermostat may be the cause of your home heating problem. For example did you know a tiny adjustment arm on some types of thermostats called a heat anticipator can make your furnace cycle on or off frequently? It can even cause your furnace to not hold a proper temperature setting.
When you troubleshoot your gas furnace you should also make sure you know how to check your thermostat's operation too, since some thermostat "furnace problems" are actually due to an improperly working or adjusted thermostat and have symptoms similar to a furnace problem.