Ecobee
Improper Heat/Cool Changeover or Reversing Valve Configuration
Thermostat calls for heat and cool at the same time or rapidly switches between them
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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
Heat pump O/B reversing valve misconfigured, Auto mode with too narrow heat/cool separation, Crossed wiring between W and Y, Faulty reversing valve in heat pump
How to Fix / Troubleshooting
Safety: Turn off power to furnace/air handler and outdoor unit before adjusting wiring.
- Step 1 – Check system mode: Avoid using Auto mode in borderline seasons; use Heat or Cool explicitly.
- Step 2 – Increase heat/cool separation: In Thresholds, increase the minimum temperature separation between heating and cooling setpoints.
- Step 3 – Verify O/B setting: In Equipment, ensure the reversing valve (O/B) is set correctly for your heat pump (energized in cool vs. heat).
- Step 4 – Inspect wiring: Confirm W, Y, and O/B wires are correctly landed at both thermostat and equipment.
- Step 5 – Call technician if reversing valve is stuck: If wiring and settings are correct but the system still heats and cools incorrectly, the reversing valve may be mechanically stuck or its coil failed.
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Repair Difficulty
Hard
4/5
Required Part
Heat Pump Reversing Valve
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