Furnace starts inducer but ignition does not occur; no flame is established.

Safety first: Disconnect electrical power and shut off gas before touching the burner or igniter area.

Steps:

• Remove the burner access panel to locate the hot surface igniter mounted near the first burner.
• Inspect the igniter element for visible cracks, white spots, or breaks. Do not touch the element with bare fingers; oils can shorten its life.
• Check the igniter plug and wiring harness for loose connections or heat damage. Reseat the connector at both the igniter and the CTC control board.
• With power OFF, test igniter resistance using a multimeter. A typical silicon carbide igniter will read in the tens of ohms; an open reading indicates a failed igniter.
• If the igniter is open or visibly damaged, replace it with the correct CTC hot surface igniter model specified for your furnace.
• After replacement, restore power and gas, then call for heat and observe the ignition sequence through the sight glass.

Note: If the igniter never receives voltage, the issue may be with the control board or safety interlocks; professional diagnosis is recommended.