Carrier H3 Error Code
Compressor overload protection
Source: hvac/carrier/00f68496__38gvq012-301__crr-38-40gvc-q-2si-english-im.pdf
What does Carrier H3 mean?
Carrier's compressor overload protection has tripped. The repair method points to checking the overload wiring, and on some models the cause extends to a compressor shell overheating or a low charge. The control shuts the compressor down to protect it from an overload condition until the cause is corrected.
Symptoms
- H3 shown on the indoor unit display
- Compressor stops under load
- Possible compressor shell overheating
- Reduced or interrupted output
Common causes
- Compressor overload condition
- Overload wiring fault
- Compressor shell overheating
- Low refrigerant charge contributing to overload
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Diagnostic steps
Confirm H3 on the indoor display
Read the code at the indoor unit, which reports faults for both units.
Check the overload wiring
Follow the manual's repair method and inspect the compressor overload wiring.
Check for overheating and charge
On affected models, confirm the compressor shell is not overheating and the charge is not low.
Correct and retest
Address the wiring, overheating, or charge cause, then confirm H3 clears.
When to call a professional
Compressor overload faults can indicate electrical, cooling, or charge problems that need meter and gauge diagnosis, so a licensed HVAC technician should investigate. Checking compressor wiring and shell temperature involves line voltage and hot components, and charge issues require certified refrigerant handling. Have a qualified professional find the underlying cause rather than simply resetting the protection.
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Other Carrier Error Codes
System high-pressure protection
Anti-freeze protection
Discharge temperature sensor malfunction (out of range)
Low-voltage protection
Communication malfunction
System overload protection
Indoor PCB malfunction
Low charge
Return air temperature sensor malfunction
Indoor pipe temperature sensor malfunction
Outdoor ambient temperature sensor malfunction
Condenser temperature sensor malfunction (open or shorted)