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S2125 does not start

NIBE S2125 does not start

NIBE · S-Series Heat Pumps

What does S2125 does not start mean?

The Heat Pump S2125 is not turning on or beginning its operation. This can be due to various reasons, including no demand for heating/cooling/hot water, temperature conditions, or an active alarm.

Common Causes

  • No demand for heating, cooling or hot water from the indoor module/control module.
  • Compressor blocked due to the temperature conditions (outside working range).
  • Minimum time between compressor starts has not been reached.
  • An alarm has tripped, preventing startup.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check the indoor module/control module to ensure there is an active demand for heating, cooling, or hot water.

  2. 2

    Allow at least 30 minutes for the system to equalize or for the minimum time between compressor starts to elapse, then check if it starts.

  3. 3

    Check the indoor module/control module display for any active alarms and follow their specific instructions.

  4. 4

    Verify that all supply cables to the Heat Pump are securely connected and main fuses are not tripped.

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 40)Search more codes in this manual