Indoor unit displays P1, and the system may not run or may shut down under load.

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.

Possible Causes

Supply voltage outside the allowable range, loose power connections at the disconnect or breaker, undersized wiring causing voltage drop, utility power issues.

How to Fix / Troubleshooting

Safety: Turn OFF power before tightening any electrical connections. Only qualified persons should measure live voltage.

Step 1 – Check Other Appliances: If lights dim or other appliances behave oddly, there may be a general power issue. Contact your utility if needed.
Step 2 – Inspect Connections: With power OFF, check that all lugs at the outdoor disconnect and breaker are tight and free of corrosion.
Step 3 – Voltage Measurement: Have a qualified technician measure the line voltage at the unit while it is running. Compare to Carrier specifications.
Step 4 – Correct Wiring Issues: If undersized or damaged wiring is found, have it replaced by an electrician.

Repair Difficulty

Hard 4/5

Required Part

Line Voltage Supply Wiring

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