Ruud Furnace Error Codes

Error Code What this means How to fix it
LED is steadily on Normal fault detected.
Single LED flash Failed to detect flame within three attempts for ignition, 1-hour lockout. Reboot system.
Two LED flashes The pressure switch is stuck open or induced draft blower problem detected. Try to manually close the switch, replace the switch, or check blowers and vents for air pressure.
Three LED flashes The limit switch is open, or the roll-out control is engaged. Check for a restricted air vent, loose blower wheel, a defective blower, or a dirty air filter.
Four LED flashes The pressure switch is stuck closed, or the switch won’t open. Check for an obstruction in the pressure tubing.
Five LED flashes N/A
Six LED flashes Line and Neutral are reversed. Control board or the furnace’s ground could be defective.