Ruud error code 14 means the R921T furnace is detecting flame when the gas valve should be off. Treat this as a critical gas-safety fault.
Professional service only
Error code 14 indicates that the furnace control senses flame when the gas valve should be off. The R921T troubleshooting table classifies this as an extremely critical fault and prevents normal furnace operation.
Flame may be present outside the normal ignition sequence; indoor blower runs at maximum heat speed; inducer runs at high speed; thermostat calls are ignored; codes 14 and 10 may alternate after the condition clears.
Gas valve stuck open; incorrect 24-volt field wiring energizing the gas valve; faulty integrated furnace control falsely detecting or commanding flame.
1. Do not attempt normal homeowner troubleshooting. 2. Turn the thermostat off. 3. If flame remains present or you smell gas, leave the building immediately without operating switches. 4. Contact the gas supplier or emergency services from a safe location. 5. A qualified HVAC technician must inspect gas-valve operation, low-voltage wiring, the control board, and the combustion system before the furnace is returned to service.
Gas valve; integrated furnace control; low-voltage gas-valve wiring; burners; flame-sensing circuit.
Immediately. The furnace should not be operated until a qualified technician identifies and corrects the cause.
If you smell gas or flame remains present, leave immediately and contact the gas supplier or emergency services from outside. Do not reset or continue operating the furnace.
Learn more about the furnace components and operating conditions commonly associated with diagnostic error codes: