CodeRegistry
Brands
  1. Home
  2. Fujitsu
  3. Air to Water Heat Pumps
  4. 3 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.

3 Flashes (Outdoor Unit)

Outdoor Unit LED 3 Flashes — Pressure switch error

Fujitsu · Air to Water Heat Pumps

What does 3 Flashes (Outdoor Unit) mean?

The LED on the outdoor unit flashes three times. This indicates a problem with a pressure switch in the system, which monitors refrigerant pressure.

Common Causes

  • Faulty pressure switch.
  • Loose or damaged wiring to the pressure switch.
  • Abnormal refrigerant pressure (too high or too low) triggering the switch.
  • Low refrigerant charge or system blockage.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Restart the heat pump system by turning off the main power for at least one minute, then switching it back on.

  2. 2

    Check the outdoor unit for any signs of refrigerant leaks (frost, oil residue).

  3. 3

    Ensure adequate airflow around the outdoor unit and clean any obstructions.

  4. 4

    If the error persists, contact a qualified technician, as pressure-related issues often require specialized tools and refrigerant handling.

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