Homeowner Guide
If the thermostat calls for heat and the furnace stays silent, clicks once, or only makes a short attempt, the useful details are what starts, what never starts, and whether any safety warning appears.
Check that the thermostat is set to heat, the set temperature is above the room temperature, the display is on, and the filter is not completely blocked. Then watch the furnace response without opening panels: silent, clicking, humming, blower only, inducer only, burners never lighting, or a short start attempt.
A furnace that will not turn on can involve thermostat control, power, safety switch, ignition, inducer, blower, gas supply, limit, or board behavior. The $95 Springfield Diagnostic is built to confirm the cause before repair pricing starts. Nearby towns may cost more.
Read the diagnostic pageDo not keep cycling the furnace for another clue. If you smell gas, leave the area and contact the gas utility or emergency services from a safe location. If you see smoke, arcing, a hot electrical smell, a burning plastic smell, or another breaker trip, shut the system off and stop testing.
