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187

Alarm 187 - Inverter Low Level Alarm

Lennox · PRODIGY 2.0 Unit Controller

What does 187 mean?

The inverter has detected a low-level issue affecting performance. This could be related to compressor current, heat sink temperature, or PFC input current. The system may automatically reduce compressor speed.

Common Causes

  • Inverter error code detected
  • High compressor current
  • High heat sink temperature
  • High PFC input current

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    If the alarm continues after outdoor conditions improve, check the fan, refrigerant charge, and coil.

  2. 2

    Refer to the service manual's troubleshooting guide for detailed information.

  3. 3

    The alarm will automatically clear when the minimum off time expires.

Browse all codes in this manual (56)
Verified technical data. Last updated: April 2026

Related Faults

12Alarm 12 - High Pressure Switch S414Alarm 14 - High Pressure Switch S716Alarm 16 - High Pressure Switch S28
Source: Lennox PRODIGY 2.0 Unit Controller
Open Manual (Page 139)Search more codes in this manual