E5
Miller
Communication or Internal Control Fault
Miller furnace digital display shows E5; unit may not respond to thermostat.
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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
Defective control board, Corrupted firmware, Shorted low-voltage wiring, Incorrect accessory wiring
How to Fix / Troubleshooting
Safety: Turn off power before working on control wiring or replacing boards.
- Power cycle: Turn off the breaker for 1–2 minutes, then restore power to reset the control.
- Inspect low-voltage wiring: Look for pinched, shorted, or miswired thermostat and accessory wires. Correct any issues.
- Disconnect accessories: Temporarily disconnect humidifiers, air cleaners, or other add-ons from the control board to see if the error clears.
- Replace control board: If E5 persists with clean wiring, replace the Miller integrated furnace control with the correct part number.
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Repair Difficulty
Hard
4/5
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