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329

Alarm 329 - Overheated inverter (Temporary)

NIBE · S-Series Heat Pumps

What does 329 mean?

The inverter has temporarily reached its maximum working temperature 3 times within 2 hours or continuously for 1 hour, indicating overheating.

Common Causes

  • Incorrect connection in the inverter’s terminal block X1.
  • Poor cooling of the inverter (e.g., blocked airflow, high ambient temperature).
  • Internal fault in the inverter.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Ensure that the area around the Heat Pump's inverter compartment has adequate ventilation and is not obstructed.

  2. 2

    Check that the outdoor ambient temperature is within the Heat Pump's specified operating range.

  3. 3

    Turn off the Heat Pump at the main power switch for at least 15-30 minutes to allow the inverter to cool down completely, then restart.

  4. 4

    If the problem recurs, contact a qualified NIBE service technician to inspect connections and cooling.

Browse all codes in this manual (55)
Verified technical data. Last updated: April 2026

Related Faults

212Alarm 212 - Low lp cooling (Low low-pressure in cooling circuit)233Alarm 233 - Fan alarm from Heat Pump234Alarm 234 - Exchange sensors flow / return
Source: NIBE S-Series Heat Pumps
Open Manual (Page 43)Search more codes in this manual