11
Rheem Internal Control Board Fault

Status LED flashes 11 times; furnace may not start or may behave erratically

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Failed control board relay, Damaged microprocessor, Surge or lightning damage, Corroded board connectors

How to Fix / Troubleshooting

Safety first: Turn off power before touching the control board or wiring.

  • Inspect board visually: Look for burnt traces, swollen components, or corrosion on the Rheem integrated furnace control (IFC) board.
  • Check connectors: Reseat all multi-pin plugs and low-voltage connections. Ensure no pins are bent or pushed out.
  • Verify proper voltage: Confirm 120V to the board and 24V from the transformer. A failing transformer can mimic board issues.
  • Replace board if needed: If power and field components test good but the board still shows an internal fault, replace with the exact Rheem-approved control board model.

Label all wires and take photos before removing the old board to ensure correct installation.

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Repair Difficulty

Hard 4/5

Required Part

Integrated Furnace Control Board
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