H3
Fraser-Johnston
Compressor Overload Trip / Internal Thermal Protection
H3 error, compressor does not start or shuts down quickly in any mode
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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
High head pressure from dirty condenser, Low suction from restricted airflow, Failing compressor, Incorrect supply voltage
How to Fix / Troubleshooting
Safety: High voltage and moving parts present. Turn off power before inspection.
- Check airflow: Ensure both indoor and outdoor coils are clean and filters are clear.
- Verify fan operation: Confirm both indoor blower and outdoor fan are running at correct speeds.
- Measure voltage: Have a qualified person verify supply voltage at the condenser matches nameplate.
- Allow cool-down: Leave power off for 30–60 minutes to allow the compressor internal overload to reset, then test again.
- If H3 returns: Compressor may be failing mechanically or electrically; professional replacement is likely required.
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Repair Difficulty
Professional Required
5/5
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