To troubleshoot a Heil furnace, perform basic maintenance techniques, such as replacing the filter and checking the power, and reference the owner's manual for model-specific tips. If common troubleshooting tips do not resolve the issue, consult a professional technician.
Furnace filters cause a large percentage of furnace issues, and they need to be replaced every month or two. Dirty filters can reduce the furnace's efficiency and can even cause the furnace to shut down completely, so they are a likely cause for many potential issues. Replace the filter first when troubleshooting a furnace.
If the furnace fails to turn on, there may be a lack of power coming to the unit, either from the main electrical panel, the thermostat or at the furnace switch. Make sure all of the components are on, and ensure the furnace is set to the "heat" setting with the temperature set higher than the room's current temperature.
The heating components are also a common problem area for furnaces. There are several components that can cause a furnace to stop heating, including the igniter, draft inducer motor, control board, flame rollout limit switch, gas valve assembly and pressure switch. Inspect these and other components to determine the problem. If the above troubleshooting tips do not solve the issue, reference the owner's manual or consult a professional for support.