E8
Westinghouse
Line voltage polarity or grounding error
Furnace displays E8 and will not run; may occur after a power surge or wiring work.
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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
Hot and neutral reversed at furnace junction box, Missing equipment ground, Shared neutral or miswired service switch, Damaged integrated furnace control from miswiring
How to Fix / Troubleshooting
High-voltage safety: This involves 120/240 V wiring. If you are not experienced with electrical work, contact a licensed electrician or HVAC technician.
Checks:
- Turn off the breaker feeding the furnace.
- Remove the electrical junction box cover on the furnace and inspect wire connections: hot (usually black) to L, neutral (white) to N, and green/bare to ground screw.
- Verify that the furnace chassis is bonded to ground.
- Use a plug-in outlet tester or multimeter at the service switch/outlet feeding the furnace to confirm correct polarity and ground.
- Correct any reversed hot/neutral or missing ground connections.
- If wiring is correct and E8 remains, the IFC may have been damaged and require replacement.
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Repair Difficulty
Hard
4/5
Required Part
Integrated Furnace Control Board
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