E7
Westinghouse
Mode Conflict / Indoor-Outdoor Mismatch or Reversing Valve Control Fault
Indoor unit shows E7 and will not start the outdoor unit; sometimes fan runs but no cooling or heating.
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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
Incorrect wiring of reversing valve coil, incompatible indoor and outdoor units, failed reversing valve coil, outdoor PCB mode control failure
How to Fix / Troubleshooting
Safety: Disconnect power to both indoor and outdoor units before opening panels.
Steps:
- Confirm model compatibility: Check that the indoor and outdoor units are matched Westinghouse models as specified in the installation manual.
- Inspect reversing valve wiring: In the outdoor unit, locate the reversing valve coil and verify that its wires are correctly connected to the PCB terminals.
- Check coil resistance: With a multimeter, measure the resistance of the reversing valve coil. An open circuit indicates a failed coil that must be replaced.
- Look for shorts: Inspect wiring for insulation damage or contact with sharp metal edges that could cause shorts.
- PCB output: If the coil is good, the outdoor PCB may not be sending the correct voltage to the coil. This requires advanced diagnostics and likely PCB replacement.
Note: Replacing a reversing valve or PCB involves refrigerant circuit work and should be performed by a licensed HVAC technician.
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Repair Difficulty
Professional Required
5/5
Required Part
Reversing Valve Coil
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