RUUD ULTRA SERIES FURNACE General Troubleshooting

Flame Sensor Rod

The flame sensor utilizes flame rectification to confirm combustion; carbon deposits create an insulating layer that prevents the micro-amp signal from reaching the control board. When the board fails to 'see' the flame within the safety window, it closes the gas valve to prevent unburned fuel accumulation but keeps the blower energized to purge the furnace.

SKU: 62-23543-01

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High Limit Switch

This bimetallic safety switch opens if the heat exchanger exceeds a specific temperature threshold, typically due to restricted airflow. Once tripped, the gas valve circuit is broken for safety, while the control logic forces the blower to run indefinitely to lower the internal temperature, resulting in cold air being circulated through the ducts.

SKU: 47-25350-01

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Integrated Furnace Control (IFC) Board

The control board acts as the central logic unit; a sticking relay on the board can cause the blower motor to stay energized even when there is no call for heat or when the ignition sequence has failed. If the logic path for the inducer motor or igniter is damaged, the board will fail to initiate combustion but will still process the fan-on command.

SKU: 62-24140-04

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