Trane
Dehumidification Control Misconfiguration
Thermostat does not control whole-home dehumidifier or overcools to dehumidify
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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
Dehumidifier not enabled or wrong type selected, Miswired DHUM or dehumidifier terminals, Dehumidify using AC mode set incorrectly, Failed dehumidifier control board
How to Fix / Troubleshooting
Safety: Turn off power to the dehumidifier and HVAC system before working on wiring.
- Step 1 – Verify configuration: In installer setup, ensure the dehumidifier is enabled and the correct control method (standalone vs AC-based) is selected.
- Step 2 – Check setpoint: Confirm the dehumidification setpoint is below current indoor humidity.
- Step 3 – Inspect wiring: At the indoor unit and dehumidifier, verify low-voltage wiring matches Trane’s diagram and that DHUM or control terminals are correctly connected.
- Step 4 – Test dehumidifier: In test mode, command dehumidification and check for 24 VAC at the dehumidifier control input.
- Step 5 – Adjust AC dehumidify settings: If the thermostat is overcooling excessively, increase the maximum overcool limit or disable dehumidify using AC.
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Repair Difficulty
Hard
4/5
Required Part
Trane Whole-Home Dehumidifier or Trane Smart Thermostat
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