E20
Kelvinator
Mode Control or Thermostat Configuration Fault
Kelvinator furnace shows E20 and cycles between heating and cooling modes unexpectedly (on dual-fuel or integrated systems)
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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
Misconfigured multi-stage thermostat, Incorrect wiring between heat pump and Kelvinator furnace, Control board dip switches set incorrectly, Faulty thermostat sending mixed calls
How to Fix / Troubleshooting
Safety first: Turn OFF power to both the furnace and any connected outdoor unit before changing wiring.
- Verify thermostat type: Ensure the thermostat is programmed for the correct system type (gas furnace, dual fuel, or heat pump with gas backup) per Kelvinator installation instructions.
- Check wiring diagram: Compare the actual wiring at the furnace control board and thermostat to the Kelvinator wiring diagram on the furnace door. Correct any miswired Y, W, or O/B terminals.
- Review dip switch settings: On the control board, verify dip switches for staging, fan control, and heat pump interface are set per the installation manual.
- Test in HEAT only: Temporarily set the thermostat to HEAT only mode and disable any automatic changeover. If E20 clears, the issue is likely thermostat configuration.
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Repair Difficulty
Hard
4/5
Required Part
Wall Thermostat
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