H4
Rheem
Indoor–Outdoor Mismatch or Configuration Error
Rheem inverter system displays H4 and may not start; indoor unit may show standby only.
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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
Incorrect combination of indoor and outdoor units, Wrong capacity code set on PCB, Firmware mismatch between boards, Incorrect dip switch configuration
How to Fix / Troubleshooting
Safety first: Turn off power to the entire system.
- Verify model compatibility: Check that the indoor and outdoor Rheem model numbers are approved to work together per Rheem documentation.
- Check capacity settings: On some models, dip switches or jumpers set capacity or system type. Verify they match the installed equipment.
- Board replacement history: If a board was recently replaced, confirm the correct part number and that any required configuration steps were completed.
- Service tools: Some H4 conditions require Rheem service software to clear or reconfigure. Contact an authorized Rheem technician.
Warning: Do not mix non-approved indoor and outdoor units; this can cause repeated faults and equipment damage.
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Repair Difficulty
Hard
4/5
Required Part
Rheem Indoor and Outdoor Control Boards (Configuration)
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