Thermostat Troubleshooting and Repair
Some common symptoms exhibited by the furnace may actually be due to a faulty thermostat. After you have confirmed that the furnace is not the problem, you'll want to check the thermostat.
Thermostat problems can show up as a furnace that produces no heat, wild temperature swings or cycling on and off too often. As described in the previous section Thermostat and Furnace Compatibility, you need to determine what type of thermostat you have for your furnace.
See the tutorial Troubleshooting a Home Furnace Thermostat for a great overview of how to repair this device.
