What It Means
Incoming AC line voltage rose above allowable operating threshold.
Carrier Heat Pump
Carrier Heat Pump Error Code 15-94
Troubleshooting guide for the Carrier Heat Pump system fault 15-94.
Possible Causes
- Utility overvoltage condition.
- Open neutral conductor on single-phase supply.
- High line voltage spikes.
Not sure which one it is — or if it's none of these? Try ACLogics today.
Disclaimer: This information is for general reference. Error codes can vary by model and production year. Always refer to your machine's specific manual and the information printed on the unit itself.
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Full Diagnosis
Line Voltage High. Incoming line voltage rose above allowed thresholds; unit will not operate or will shut down while active.
All Recorded Causes
Measure supply voltage at disconnect. Check for utility overvoltage condition. Inspect for open neutral on single-phase supply. Contact utility company if supply voltage is consistently high.
Verify Before Replacing Parts
- Confirm the exact Carrier model family and heat pumps context before acting on a generic code description.
- Start with line voltage, low voltage, and board output checks in sequence so the fault is isolated cleanly — the data plate flags measure supply voltage at disconnect.
- Inspect connectors, relay outputs, and any recently replaced electrical parts for mismatch or loose fit, and verify check for utility overvoltage condition.
- After the correction, run the system long enough to confirm the heat pumps fault does not return under normal load.
Still unsure about this fault?
ACLogics walks you through Carrier Heat Pump diagnostics step-by-step — so you confirm the cause before swapping parts.
