Ruud Furnace Error Codes: R96T, 22 and 33

Keep both digits and any second code

The R96T manual describes a seven-segment display. A two-digit fault appears as the first digit, then the second digit, followed by a pause. If two faults are present, the display can alternate between them. A short video helps preserve their order without removing a door.

Its normal-operation table identifies 0 as standby with no fault and no thermostat call. Uppercase H means high gas heat, lowercase h means low gas heat, and F means a continuous fan call. Those letters describe operating modes rather than faults.

The same table uses C for cooling or heat pump operation. Record the actual symptom as well: a mode letter alone does not explain why a room is cold. If you cannot see a display with the cabinet closed, use the thermostat message and let service read the board.

Keep the original fault with a lockout message

The R96T manual defines 10 as one-hour lockout. It can accompany failed ignition, lost flame, water-sensing, blower or other faults described in the detailed table. Do not reduce an alternating 10 and 11 sequence to just “lockout.”

The manual defines 11 as failed ignition. It describes four consecutive failed ignition attempts leading to lockout, with 10 and 11 alternating. Its possibilities include a flame-sensing problem, a gas valve turned off, an igniter problem or a control problem.

Code 12 is low flame sense. The manual says operation can continue with that message while flame-sense current is weak or marginal. Code 13 means a flame that was established is no longer sensed during a valid heat call.

Give service the exact sequence and what happened before it. Leave flame-sensor cleaning, igniter positioning, wiring and gas-pressure checks to the technician. The manual’s corrective actions are service procedures, not owner steps inside the burner compartment.

Do not press a rollout reset or bypass a limit

The R96T table defines 22 as the main limit open or sensed open. Its possibilities include no or insufficient airflow, a faulty limit, loose wiring, a nonfunctional blower and excessive input. The manual describes the blower running at maximum heating speed while the gas valve circuit is de-energized.

Note whether accessible room registers or return grilles are covered. The manual’s customer instructions say to keep those openings unobstructed and filters clean. After any unsafe condition has been addressed, disconnect the furnace’s main electrical power before filter maintenance and follow the installed filter arrangement’s owner instructions. Refit the filter and secure all doors and covers before operation. Do not remove a service panel to investigate a limit fault.

The manual defines 33 as the manual-reset rollout limit circuit being open. Its description calls this a serious problem requiring repair before furnace operation continues. Possible causes include insufficient inlet or exhaust venting, loose or faulty wiring and an unstable flame pattern.

The words “manual reset” name the control. They do not authorize an owner restart. Apply the manual’s safety-switch warning above and have a qualified person investigate before any reset.

Report the code instead of ordering a switch

The R96T manual distinguishes switches that are closed before the inducer starts from switches that remain open while it runs. Preserve the exact number:

For the open pressure-switch rows, the manual lists vent restriction, an inducer problem, wiring, hoses and the pressure switch among possible causes. That list requires diagnosis; it does not prove the switch has failed.

The detailed drain rows also separate 58 from 59. An open water-sensor circuit is different from detected water. Report visible leakage from a safe position, but leave trap removal, sensor work and internal drain repairs to service. Do not bridge a sensor to make heat return.