LED flashes code 22; furnace will not start heating cycle, inducer may not run.

Warning: A flame signal when gas should be off can indicate a dangerous condition. Shut off gas and power before inspection.

• Step 1 – Inspect flame sensor wiring: Disconnect the flame sensor wire at the sensor and the control board. Check for continuity to ground; there should be no continuity. Replace the wire if it is shorted.
• Step 2 – Check flame sensor mounting: Ensure the sensor is mounted correctly and not touching the burner in a way that could create a constant ground path mimicking a flame signal.
• Step 3 – Inspect gas valve: With gas off, check for any odor of gas near the burners. If you suspect the Tempstar gas valve is leaking through when closed, contact a licensed gas technician to test and replace the valve.
• Step 4 – Examine control board: If wiring and valve are good, the flame-sensing circuit on the control board may be defective. Inspect for burn marks or corrosion. Replace the Tempstar integrated control board if necessary.
• Step 5 – Restore operation: After repairs, restore gas and power, then initiate a call for heat and verify that the code clears and the furnace cycles normally.