Skip to main contentStart diagnosing E:08 on your Bosch water heater
What this code means
Heat pump error - one of several possible causes including faulty heat pump, faulty power module or insufficient water supply. Possible causes: Faulty heat pump; Faulty power module; Insufficient water supply
Next steps: diagnose the root cause
1
Verify the error code is active
Power cycle the unit and see if the code returns. If it does, the fault is persistent and requires diagnosis.
2
Get the full diagnostic procedure
Get step-by-step guidance, test values, and wiring diagrams from the OEM service manual.
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What’s available for Bosch water heater models
Access Bosch water heater service manuals, wiring schematics, exploded parts views, and error code references on MyPros+.