CodeRegistry
Brands
  1. Home
  2. Fujitsu
  3. Air to Water Heat Pumps
  4. 8 Flashes (Outdoor Unit)
About·Privacy·Terms

CodeRegistry — Your global library for technical solutions.

For your safety: always follow the equipment manufacturer’s official manuals. CodeRegistry is an independent help site and is not affiliated with the brands listed here.

8 Flashes (Outdoor Unit)

Outdoor Unit LED 8 Flashes — Compressor thermistor error

Fujitsu · Air to Water Heat Pumps

What does 8 Flashes (Outdoor Unit) mean?

The LED on the outdoor unit flashes eight times. This indicates a problem with the thermistor that monitors the compressor's temperature.

Common Causes

  • Faulty compressor thermistor.
  • Loose or damaged wiring to the thermistor.
  • Compressor overheating due to other system issues (e.g., low refrigerant, blocked airflow).

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Power cycle the heat pump system by turning off the main breaker for 60 seconds and then restoring power.

  2. 2

    Clear any obstructions around the outdoor unit to ensure adequate airflow for cooling the compressor.

  3. 3

    Check the ambient temperature; extremely high temperatures can contribute to compressor overheating.

  4. 4

    If the error persists, contact a qualified technician, as this could indicate a faulty thermistor or an underlying compressor issue.

Browse all codes in this manual (59)
Verified technical data. Last updated: April 2026

Related Faults

1 Flash (Outdoor Unit)Outdoor Unit LED 1 Flash — Serial forward transfer error10Fault 10 — Outdoor sensor error11Error 11 (1 Green, 1 Red Flash) — Communication error between Hydraulic and Outdoor unit
Source: Fujitsu Air to Water Heat Pumps
Open Manual (Page 9)Search more codes in this manual