E7
MrCool Mode Conflict or Indoor Unit/Outdoor Unit Mismatch

Indoor unit shows E7; system may not start or may run erratically.

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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

Multiple indoor heads calling for incompatible modes on multi-zone system, Incorrect DIP switch or address settings, Incompatible indoor unit model connected to outdoor unit

How to Fix / Troubleshooting

Safety first: Turn off power before opening any covers.

User checks:

  • Align modes: On multi-zone MrCool systems, ensure all indoor units are set to the same operating mode (all COOL, all HEAT, or all FAN). Avoid mixing HEAT and COOL simultaneously.
  • Reset units: Turn all indoor units OFF, then power cycle the outdoor unit at the disconnect for 5 minutes. Turn units back on one at a time.

Installer-level checks: If E7 persists, an installer should verify indoor unit addressing, DIP switch settings, and compatibility with the outdoor model per MrCool documentation.

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Repair Difficulty

Medium 3/5
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