Fujitsu Error Code A4: High pressure error (Heat Pump)
Fujitsu error code A4 on a heat pump means: High pressure error. It is also called Fujitsu diagnostic code A4.
Homeowner? What Fujitsu code A4 means for you
Call a technician Your heat pump is reporting: High pressure error. The heat pump has locked out or cannot run properly. One reset is fine; if the code comes back, it needs a licensed technician to find the cause.
Safe things you can check yourself
- Check the thermostat: right mode (Heat or Cool), set a few degrees past room temperature, and fresh batteries if it uses them.
- Check both breakers and the outdoor disconnect box beside the outdoor unit; all should be ON.
- Look at the air filter. If it is grey and clogged, replace it; a blocked filter causes many shutdowns.
- In winter, keep snow and ice off and away from the outdoor unit. A short defrost cycle with steam is normal.
- Try one reset: turn the power off for 30 seconds, then back on. If the code comes back, stop resetting and call a technician.
Call (647) 657-2977Book a service call
Licensed technicians serving Vaughan, Toronto and the GTA.
What does Fujitsu error code A4 mean?
System high pressure too high. Indoor lamps: OPERATION (green) flashes 10x, TIMER (orange) flashes 4x, ECONOMY (green) flashes fast nonstop; wired remote shows A4.
Applies to: Fujitsu ductless heat pumps: Fujitsu ductless split/multi/VRF (general code list), Fujitsu wall-mounted 7-15 (NA ASU/AOU type), Fujitsu slim duct ARU 7-18 (LL type)
Common causes of Fujitsu code A4
- Blocked outdoor coil / fan fault (cooling)
- Indoor airflow low (heating)
- Overcharge / non-condensables
A technician checks these and 1 other possible causes on site before replacing any part.
Other Fujitsu Heat Pump codes
All Fujitsu Heat Pump error codes →
Fujitsu code A4: homeowner questions
What does Fujitsu code A4 mean?
High pressure error. System high pressure too high. Indoor lamps: OPERATION (green) flashes 10x, TIMER (orange) flashes 4x, ECONOMY (green) flashes fast nonstop; wired remote shows A4.
Is it safe to keep using my heat pump with code A4?
It depends on the cause. The heat pump has locked out or cannot run properly. One reset is fine; if the code comes back, it needs a licensed technician to find the cause.
Can I reset Fujitsu code A4 myself?
You can try one reset (power off for 30 seconds, then on). If Fujitsu code A4 comes back, the cause is still there and a licensed technician should check it.
Who can fix Fujitsu code A4 near me?
Aurora Star Tech Inc. repairs Fujitsu heat pumps in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.
Homeowner help: AC Running But Not Cooling: What to Check · Heat Pump Not Heating or Blowing Cold Air
Source: Fujitsu All Fujitsu split - multi - VRF (generic code list) codes.pdf - section error code table (indoor LED flashes); Fujitsu Wall-mounted 7-9-12-15 (North American trilingual, UTY-RNNUM remotes; e.g. ASU9-12-15 RLF1-RLS familie.pdf - section 14 Error codes; Fujitsu Slim duct AR07-09-12-14-18 (ARU-ARYG LL-type equivalent) installation P-N 9381858064.pdf - section 14 Error codes. Written in our own words as a summary; always check the original manual.
General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.