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Error code reference
GE Heat Pump Error Code 21
Indoor unit overload protection (heating mode) / Indoor coil frosted - anti-freezing cycle initiated.
SourceDuctless Multi-Split Heat Pump - Full Service ManualB-23, J-18
Diagnostic procedure
The full 21 procedure
Step 1 is visible so you can confirm you are on the right page. The remaining steps, the ones that tell you whether to actually replace a part, unlock with any pass.
MyPros+ · DiagnosticsStep 1 preview
1
First diagnostic step
Check for lack of heat in conditioned space, excessively cold air temperature, blocked airflow, or indoor fan motor issue.
SourceDuctless Multi-Split Heat Pump - Full Service ManualB-23, J-18
More steps, wiring diagram references, and verified part numbers
Includes expected resistance and voltage values, connector pinouts, and supersession notes for replacement parts.
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Where this code is documented
1 manual in the MyPros+ library documents this code for GE heat pump.
Models covered by the manuals that document this code
75,000+ service documents · 20,000+ error codes · 100+ brands
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