ErrorCodeDoctor
Daikin Air Conditioner H4 error code
The H4 error means your Daikin air conditioner detected a fault with the low pressure switch itself. Contact a qualified technician to inspect and replace the low pressure switch.
Common causes
- Defective low pressure switch
- Broken wire to the low pressure switch
- Defective outdoor unit PCB
- Defective connector contact
How to fix it
-
1
Contact a qualified technician to inspect and replace the low pressure switch
Related Daikin Air Conditioner error codes
A0
An external protection device connected to the indoor unit has been activated
A1
A fault was detected in the indoor unit PCB (control board)
A3
The drain level control system has detected an abnormality — drain may be clogged
A5
Freeze-up protection (cooling) or high pressure control (heating) has activated — check the air filter
H4 error — frequently asked questions
What does the H4 error mean on a Daikin air conditioner?
The low pressure switch (LPS) has a fault
What causes the H4 error?
The H4 error is usually caused by: Defective low pressure switch; Broken wire to the low pressure switch; Defective outdoor unit PCB; Defective connector contact.
Can I fix the H4 error myself?
This is rated a hard fix — it often requires tools, parts, or experience, and may be safer left to a professional technician.
How much does it cost to fix the H4 error?
Fixing the H4 error on a Daikin air conditioner typically costs $80–$250, depending on parts and whether you do it yourself or hire a technician.
Is it safe to keep using my air conditioner with the H4 error?
We'd recommend addressing the H4 error before continuing to use the air conditioner, since hard-rated issues often involve a real fault rather than a minor glitch.