Ruud Furnace Error Codes

Error CodeWhat this meansHow to fix it
LED is steadily onNormal fault detected.
Single LED flashFailed to detect flame within three attempts for ignition, 1-hour lockout.Reboot system.
Two LED flashesThe 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 flashesThe 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 flashesThe pressure switch is stuck closed, or the switch won’t open.Check for an obstruction in the pressure tubing.
Five LED flashesN/A
Six LED flashesLine and Neutral are reversed.Control board or the furnace’s ground could be defective.