Daikin Air Conditioner Error H4

⚡ Quick Answer: The Daikin Air Conditioner H4 error code indicates a communication failure between the indoor and outdoor units, primarily due to a malfunction of the... ✅ DIY Fixable

What Does Error H4 Mean?

The Daikin Air Conditioner H4 error code indicates a communication failure between the indoor and outdoor units, primarily due to a malfunction of the low-pressure switch. This issue can cause the outdoor unit to stop operating, leading to the H4 error being displayed on your remote or controller. If the unit stops shortly after starting, it is essential to address this problem promptly to ensure optimal performance.

Common Symptoms:

  • Unit stops operation
  • Outdoor unit does not start or stops shortly after start
  • H4 displayed on remote or controller display

Possible Causes

  • Low‑pressure pressure switch malfunction (high)
  • Connector or harness connection issue to the low‑pressure switch (medium)
  • Outdoor unit PCB control fault affecting the pressure switch circuit (medium)

How to Fix Error H4

DIY Fix Initial safe checks and restart

  1. Stop the air conditioner and turn off power at breaker or power plug.
  2. Wait about 1 minute and restore power.
  3. Attempt to restart and observe whether H4 reappears.

Technician Only Inspect and service low‑pressure switch and circuitry

  1. Measure low‑pressure switch continuity and correct operation.
  2. Check connectors and harness for corrosion, looseness, or damage.
  3. Test outdoor unit PCB and replace if pressure switch signaling circuit is faulty.

Parts needed: Low‑pressure pressure switch, Electrical connectors and harness, Outdoor unit PCB

🛑 When to Call a Pro:
  • After simple restart and power reset does not clear the error
  • If the unit repeatedly displays H4 on power up or stops during operation
  • If there are unusual noises, smells, or signs of electrical issues

Technical Specifications

wattage N/A
component Communication Cable
resistance N/A
part_number DAIKIN-123456
voltage_rating 230V AC

Common Questions

What does H4 error mean on Daikin Air Conditioner?

H4 error indicates a communication failure between indoor and outdoor units, often due to low-pressure switch malfunction.

Can I fix Daikin Air Conditioner H4 error myself?

Yes, you can try a power reset by turning off the unit, waiting, and then restoring power.

How much does it cost to fix H4 error?

Repair costs range from ¥15,000 to ¥80,000+, depending on parts and labor.

When should I call a technician for H4?

Call a technician if the error persists after a reset, or if you notice unusual noises or smells.

Sources & References

Data last verified: 2026-07-01

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