Trane error 91 troubleshooting

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Trane error 91 troubleshooting

Error code 91 on a Trane HVAC system indicates a communication error between the indoor and outdoor units. Here are some troubleshooting steps you can try:

  1. Check the wiring connections: Ensure all the connections between the indoor and outdoor units are secure and tight.
  2. Check the voltage: Use a multimeter to check the voltage between the indoor and outdoor units. The voltage should be within the manufacturer’s specifications.
  3. Check the control board: Inspect the control board for any signs of damage or burnt components. Replace the control board if necessary.
  4. Check the refrigerant levels: Low refrigerant levels can cause communication errors between indoor and outdoor units. Check the refrigerant levels and add more refrigerant if necessary.
  5. Check the outdoor unit: Inspect the outdoor unit for any signs of damage or blockages. Clear any blockages and repair any damage.

If these steps do not resolve the error, it may be necessary to call a professional HVAC technician to diagnose and repair the issue.