What It Means
Incoming 230VAC line voltage dropped below acceptable threshold.
Bryant Heat Pump
Bryant Heat Pump Error Code 93
Troubleshooting guide for the Bryant Heat Pump system fault 93.
Possible Causes
- Low supply voltage under load at outdoor disconnect.
- Undersized supply conductors or long wiring run.
- Loose wiring connections or utility power dip.
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
230VAC Under Voltage Event. 230VAC under-voltage event detected.
All Recorded Causes
Measure supply voltage at outdoor disconnect under load. Check for undersized wiring or loose connections. Contact utility company if supply voltage is consistently below specification. Board retries after 15 minutes.
Verify Before Replacing Parts
- Confirm the exact Bryant 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 outdoor disconnect under load.
- Inspect connectors, relay outputs, and any recently replaced electrical parts for mismatch or loose fit, and verify check for undersized wiring or loose connections.
- 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 Bryant Heat Pump diagnostics step-by-step — so you confirm the cause before swapping parts.
