Status LED shows 1 flash, furnace will not start heating cycle, inducer and blower are off.

Safety first: Turn off power at the furnace switch and shut off gas at the gas shutoff valve before removing panels. If you smell gas continuously, evacuate and call the gas utility or a licensed technician.

Steps to check:

• Reset power: Turn furnace power off for 30–60 seconds, then back on. Observe the LED and ignition sequence.
• Verify gas supply: Ensure the manual gas shutoff valve near the furnace is parallel to the pipe (open). Confirm other gas appliances work.
• Inspect hot surface ignitor: Remove the burner access panel. Locate the hot surface ignitor on the burner assembly. Look for cracks, white spots, or breaks in the element. If damaged, replace the ignitor with the correct Ruud-compatible part.
• Clean flame sensor: Locate the flame sensor rod near the burner. Remove the mounting screw, gently clean the rod with fine steel wool or emery cloth until shiny, wipe with a dry cloth, and reinstall.
• Check wiring to gas valve and ignitor: Inspect harnesses from the control board to the gas valve and ignitor for loose plugs, burnt connectors, or damaged insulation. Reseat connectors firmly.
• If lockout persists: After 3–5 failed ignition attempts, the board may enter lockout. Power-cycle again. If the ignitor never glows or gas never flows, the control board or gas valve may be faulty and should be tested by a technician.