Ruud Furnace Error Codes
Ruud furnaces are built on the same platform as Rheem and share their controls and diagnostics. A solid value brand in BC homes, Ruud's fault conditions and LED codes match Rheem's, covered below.
How Ruud shows faults: Ruud furnaces use the same diagnostic LED codes as Rheem. The conditions below explain the common faults.
Ignition Lockout
highThe furnace ran through its ignition trials, never proved a flame, and locked out for safety. Many boards retry automatically after about an hour.
Weak or Lost Flame Signal
highThe furnace lit but the flame-sensing rod measured too little current, so the board closed the gas valve. The single most common furnace fault we see each winter in BC.
Pressure Switch Stuck Open
highThe inducer ran but the board never saw the pressure switch confirm draft, so it will not allow ignition — a venting safety interlock.
Pressure Switch Stuck Closed
moderateThe board saw the pressure switch already closed before the inducer started, treats it as a fault, and refuses to fire.
Open High-Limit Switch
highThe high-limit opened because the heat exchanger got too hot — almost always an airflow problem you should not ignore.
Flame Rollout Switch Tripped
criticalSafety-critical: flame rolled out of the burner box instead of drawing into the heat exchanger, tripping the manual-reset rollout switch. The furnace must be diagnosed by a technician before reset.
Flame Detected With No Call for Heat
criticalThe board senses flame when the gas valve should be closed — a serious gas-control fault that locks the furnace out.
Blower or Inducer Motor Fault
highThe furnace cannot run the inducer or main blower as commanded and shuts down — both are essential for safe operation.
Need a Ruud technician in Greater Vancouver?
Furnace and heat-pump service is handled by our parent company, CANRO Heating & Cooling — same-day & after-hours. Call 604-359-1081.
Ruud furnace acting up?
CANRO Heating & Cooling — same-day diagnosis across Greater Vancouver. Call 604-359-1081.