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Error code reference
Samsung Heat Pump Error Code E266
Sump Sub 1 breakaway error.
SourceSamsung Heat Pump - Troubleshooting Guide: Error Codes & Diagnostics (RMAH180GAM0SER)p. 220, 249
Diagnostic procedure
The full E266 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 if SUMP Sub 1 temperature sensor is separated; reassemble.
SourceSamsung Heat Pump - Service Manual: Troubleshooting & Error Codes (AVMWH020CA0G)p. 220, 249
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
3 manuals in the MyPros+ library document this code for Samsung 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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